Can half a million Austrians be wrong? That is the number of people that have seen Wolfgang Weinberger's lecture-meets-therapy-meets-comedy, A Guide to Sexual Misery. He is now holding court in Leicester Square attempting to liven up London's love lives, yet judging by frequent outbreaks of giggling on the first night you do not need to be Sigmund Freud to work out that Weinberger is a better humourist than sexologist.

Relationships are a well-trodden area for wit. From Woody Allen to umpteen current stand-ups tackling male and female differences, this is familiar terrain. But the benign, ever-smiling expert puts some fresh spin on it, separating the crowd down gender lines so that men and women can contribute frankly without their partners poking them in the ribs. Be warned – there is audience participation, though humming answers en masse preserves anonymity and everyone remains clothed.

Weinberger's hardly profound thesis is that we are all screwed up. Either by our parents or by our own expectations. We aim too high and are disappointed, we aim too low and are disappointed too. After four years partners communicate meaningfully for four minutes a day. Women fuss too much, husbands cannot find their way around their wives’ bodies with a torch, compass and Ordnance Survey map. 

This is the sexual misery that our host alludes to. After the interval he sets out to heal his audience's pain with a brisk question and answer session. The anxieties are predictable and our guide has plenty of cheeky answers. If a clipboard statistic cannot help there is always his trusty flipchart and a rude pie chart. It is a quick and superficial resolution, which gets plenty of easy laughs.

Despite a few intellectual pretentions and footnotes this is a basic affair. It is not a surprise to discover that Weinberger is originally a filmmaker who took over the show from the therapist who devised it. Those 500,000 Austrians cannot be particularly demanding. 

Yet there is something strangely enjoyable about hearing a cuddly man talk about sex for 90 minutes. One can imagine that on Friday and Saturday nights  this show will play to packed houses and get rather riotous. For this guinea pig, however, proceedings reminded me a little too much of my love life. There was a bit of frustration, a lot of expectation and then it was all over very quickly.

Leicester Square Theatre, WC2 until 23 May (0844 847 2475, www.leicestersquaretheatre.com)

Gordon Brown is finally a hit in America. Though perhaps not in the way he wanted. The PM has just appeared in an episode ofSouth Park as part of a posse of politicians who rob aliens to solve the recession. Never mind killing Kenny, this appearance may have killed any credibility he has in the USA. Assuming viewers even recognised him, given that he has a strangely cockney accent.

This is hardly the first time that someone in high office has appeared in a comedy show. And to be fair Gordon was an unwitting participant, which is more than can be said of previous interfaces between politics and comedy. His predecessor found time during the Iraq crisis in 2003 to do his own voiceover in The Simpsons. And Tony generously took a break from meddling in the Middle East to film a Comic Relief appearance with Catherine Tate in 2007. 

This cynical dallying with unofficial court jesters and becoming a laughing stock goes back much further of course. Neil Kinnock made a prize pillock of himself when he guested with Tracey Ullman in the video for her single My Guy in 1984. Kinnock played himself canvassing for votes but in reality probably lost more than he gained by getting on Top of The Pops. The record was pants too.

Trying to show that you have a sense of humour is never a vote-winner, but maybe the Labour Party does it a little better than the Tories. Margaret Thatcher had a bash at being down with the kids with a painfully staged cameo in a specially recorded Yes, Minister sketch in 1984. It was stilted and awkward and rather than humanise the PM it underlined her painfully profound lack of wit. 

Margaret Thatcher should have learnt her lesson from previous Tory leader Harold Macmillan, who tried to score a few credibility points with a visit to Beyond The Fringe at the Fortune Theatre in 1961. Unfortunately Peter Cook, then at the top of his satirical game, turned the tables with a bang-on Macmillan ad lib: ""When I've a spare evening, there's nothing I like better than to wander over to a theatre and sit there listening to a group of sappy, urgent, vibrant young satirists, with a stupid great grin spread all over my silly old face."

Perhaps the only politician to have got away with getting into a metaphorical bed with humourists has just passed away. Clement Freud somehow managed to combine a career in Westminster with regular stints on Just A Minute. But then he was  member of the Liberal Party, a political organisation long regarded by many as a joke. 

They call it "jumping the shark" in the TV business. This is when a hit programme starts to lose its way – the phrase comes from an episode of Happy Days where the Fonz, in leather jacket and trunks, leapt over a shark on water skis. Critics said the show was never the same again.

Well, I think The Apprentice may have hopped in that direction last night when Sir Alan packed his teams off to devise new bodycare products. I'm not saying the show is in a rut but I couldn't help feeling that when one of the teams went to sell their cobbled-together lotions and potions they did it in the same W11 spot near to the same hot dog van that another team tried desperately to hire out luxury sports cars a few years ago. 

There was a distinct feeling that scenes were set up for televisual effect. When the teams chose to put seaweed and honey in their products it meant a boat trip round Poole harbour and a visit to a hive. If they'd opted for apples and pears it would not have been quite so telegenic.

The real problem, however, came out of a bottle. Paula's team got their prices of sandalwood and cedarwood muddled up and Paula  "shall I put a fiver for that?" – and her gang were doomed. It was such a costly error (instantly around £500 over budget) Nick even had to step in and point it out – when it was too late to change it of course.

Yet it did look briefly as if they might snatch victory from the jaws of defeat. Out on London's trendiest streets they sold like their lives depended on it, while the other team struggled and ended up virtually giving their stock away to bag ladies and Big Issue sellers at Camden Lock.

Oh, if I haven't mentioned the other team it is because they were led by such an ineffectual leader they were often invisible. Noorul barely spoke, instead he wandered around with a look of fear in his eyes. But then if I had his product I'd be terrified too. His honey-filled soap looked more like a giant oozing, suppurating sore. When he hit the streets in a beekeeper's outfit to sell it it looked as if he was wearing a radiation protection suit and was demonstrating the after-effects of Chernobyl. No wonder no-one was buying.

Thanks to Paula's cedarwood-perfumed cock-up, however, Noorul's team won the task. In the boardroom blame-game it was dog-eat-dog and private sector hounds Ben and Yasmina tore public sector Paula apart. Despite having a lot of good ideas Paula got the boot. Ironic as footwear may be crucial here. As she left for her cab of death I think I spotted the reason why she didn't last. She was wearing clumpy shoes. You've got to wear stilettos in the world of The Apprentice. And that goes for the men too.  

You can't have a new episode of Dr Who without a rumour of a spin-off and sure enough, following the Doctor's Easter special Planet of the Dead comedian Lee Evans is being mooted as the co-star of his own breakaway show. In this weekend's episode Evans followed in the footsteps of Peter Kay and Catherine Tate and stole the show as obligatory comedy cameo. Dotty lab-coated boffin Malcolm Taylor was the kind of part Evans could probably have done without any rehearsals – he simply slicked down his hair, slicked up a Welsh accent and was off.

Evans had some of the bestlines in the programme – it was rather sweet that he had called a unit of measurement a "Malcolm", but beyond the overexcitable nerd stereotype there was not a lot of room for Evans to do what he does best onstage – run about like a bluebottle. That was left to the pretty dull aliens who were basically jobbing extras with giant bluebottle heads.

This was not the greatest Dr Who special by a long way. The tantalising trailers of the red London bus stranded in the desert made it look promising but it just couldn't live up to expectations. Evans being eminently watchable but not being stretched was typical of the way this yarn was severely lacking in the imagination department. Likewise those other monsters – the metallic manta ray things – felt like they have been seen in endless sci-fi romps of the past. This may have been a homage, but it felt like a lack of thought.

Meanwhile there was not much sign of sexual chemistry between David Tennant and Michelle Ryan. I'd heard rumours that Lily Allen was going to be a future Dr Who companion, but judging by Ryan's jet black fringe they clearly decided to hedge their bets and just cast her hair instead.

The appearance of Evans was a nice surprise for comedy fans but it would be have better to have had more of him. Which may be why there is talk of a spin-off. This is a character that Evans could really get his teeth into, but in this one-off he barely had a nibble.

In television there is a theory that you start with your best episodes to hook the viewer and finish with your next-best episodes to leave them wanting more. That way you can hide your weaker bits in the middle and no-one will remember them. Due to the eviction process it is not possible to juggle the running order of The Apprentice, but last night's task, which which the teams had to create a fitness machine in about twenty minutes, was one of the shallowest shows yet.

I wouldn't say The Apprentice is hurtling downhill fast, but it both felt like self-parody and was hard to get really involved in. Sir Alan (is it me or is he getting thinner each week?) did that annoying thing of mixing up the teams, which takes away the boys v girls aspect. Instead we just had some random bickering. Flat-faced Debra shouted a bit (but not as much as in the trailers for next week), while baby-faced Pub Landlord lookalike James, ostensibly a team leader, was so low-key he must have left the much-discussed success in his spit somewhere else.

Instead it was down to self-loving flabby hunk Ben to grab the limelight. His first idea was for some sex-based piece of home exercise equipment. When that idea landed on stony ground his team ended up with the Home Multi-Tone, which did everything and nothing for under £30. The boffins went off and made it and returned the next morning with something black that looked suspiciously like a hollowed-out guitar amplifier.

It was, of course, rubbish, though John Lewis ordered a few just for a laugh. The only exercise this was going to give anyone was carrying it around to the local charity shop. Was it only me that saw the advert that said "we're doomed" in the shop window where they went to get their posters printed?

Meanwhile Debra's team came up with the Body Rocka, which sounded dreadful and looked like a cross between a toilet seat and a white plastic sombrero. It was going to replace the multi-selling Swiss Ball. It was going to be the ipod of the fitness world they announced. Why didn't they just go the whole hog and call it the ibod?

I didn't see any exercise experts in give their verdicts on its usefulness, but John Lewis ordered thousands of them (presumably now languishing in their lavatory/Mexican hat department). So James' team lost, Majid got the boot for being nice and dull and Debra's team had a private gig with Katherine Jenkins, when they were probably hoping for a trip round Silverstone in helicopters or something.

And talking of Silverstone, what was all that flannel in the intro about Lee Valley Athletics Centre being one of the greatest sports venues in the country? What about Wembley, Wimbledon, Royal Birkdale, Twickenham, Lords, the bowling green in my park? It's a bit like saying that Portobello Lofts, where the contestants live and run around in the pants when Sir Alan rings, is one of the greatest apartment blocks in the country...

If these are some of Britain's best business brains then heaven help us. I've always laughed at hair-gelled high flyers who talk about giving the mathematically impossible 110% and episode two of The Apprentice had me constantly holding my sides together. This edition threw up so many classic comedy moments there isn't enough room on the world wide web to list them all.

Margaret hiding her face with her hand when Crazy Lips Kate tried to bluff her way through a pitch for a classy catering job was priceless, but then I think I have a bit of a crush on Margaret.

Then there was table-banging James, who looked like he was going to get fired, but was clearly kept in not because of his business acumen but because his one-liners are such great value. "I feel like I did when my cat died" is not something you hear every day from an aspiring city slicker. 

In the end though, it was red-cheeked sandwich shop king Rocky who got the chop. He seemed like the natural leader for the task of flogging sandwiches to hungry office workers, but he flopped at that and when it came to coming up with canapes for a swish catering gig he put on a spread that would have shamed an Iceland advert.

The combination of togas, spotty backs and cheese on sticks was never going to win any awards, but my favourite was the feeble tray of Doritos with a few dollops of something red and sticky on them. 

Customer satisfaction zero. Audience satisfaction 110%.