Last Night's TV: Viagra: Ten Years On the Rise FIVEMy New Best Friend BBC4The Apprentice BBC1

These limp gags couldn't raise a smile

"I can, hand on heart, say I've never had a tofu experience," said a journalist called Jenny Davis in Viagra: Ten Years on the Rise. Jodie Marsh had, though, and she recalled it in terms of wondering bemusement, a moment when her ability to induce turgidity had momentarily failed her. They weren't talking about food but responding to an unusual piece of equipment intended to help doctors gauge the precise extent of their patients' erectile failure. It consists of a small rack containing a cucumber, a banana, a peeled banana and a square of tofu, each of which the sufferer is invited to compare, in terms of rigidity and resilient bounce, with his own sluggish organ. The cucumber struck me as cruelly redundant, frankly, given that only men with a problem are likely to encounter this diagnostic kit. It protruded at the end as a grade-four erection, a mocking green reminder of lost glory for those still haplessly mired in the territory of the grade one (tofu) and the grade two (a peeled banana). But who knows, perhaps it offers hope as well.

In the old days, there wasn't a lot of hope around. Getting the salad- days crispness back in your erection was a laborious business involving pneumatic pumps, self-administered injections into the penis (even the female narrator gave an audible squeak at that point) or full-blown surgery. But then a pharmaceutical company testing a new heart drug discovered that their male guinea pigs were unusually reluctant to hand back the surplus pills when the trials were over – and Viagra was born. To celebrate its 10th birthday, Five had glued together this loose assembly of anecdote, innuendo and television cliché with a script that sounded as if it was sidling around a bedroom in a rubber nurse's uniform. We got saucy talk about lead in pencils and descriptions of how combat pilots had been given the drug so that they would have "better control of their joysticks". We got reversed film of factory chimneys being demolished. We got stripper jazz on the soundtrack and soft-focus reconstructions involving improbably toned models. We even got that old trope of interruption: the gramophone needle skidding across the grooves. I think the whole thing was supposed to do for our attention span what fluffers used to do for male porn stars before Viagra made them redundant, but I'm afraid it just left me with viewer's droop.

Not as much as My New Best Friend, though, a new series about children making the transition from primary school to secondary school that, on the evidence of the first episode, could successfully be marketed as an aid for insomniacs. I can't work out why this is, because there's nothing inherently dull about the lives of children and the subject here – the fraught diplomacy of playground relationships – is a perfectly good one. It proved to be a very long haul, even so. This first episode followed Daisy, Nanae, Annabelle and Lydia, four girls taking up places at Cheltenham Ladies' College, and there was the odd flicker of class tourism in watching them pack their tuckboxes and trunks for the start of term. But the real problem, as any parent will know, is that 12-year-olds aren't very forthcoming when questioned by adults about their inner feelings. "What does making really good friends mean?" one girl was asked. "I know them a bit more than I did and I play with them a lot," she answered, less than enthrallingly. "And how do you sort things out when things go wrong?" the off-camera voice inquired of another. "Well, in the end we just do, I can't really explain it," she said. I suspect that if they'd left the camera and removed the grown-up from the room – as video-diary films have successfully done with children in the past – they'd have ended up with something a lot more satisfactory.

Raef got the push in last night's The Apprentice, after both teams were asked to produce a TV ad for their own brand of anti-bacterial tissues. The winning team came up with a surprisingly plausible name for their product ("Atishu") and then crafted a pack and a pitch that were so awful they made you want to crawl under a table. Raef, however, decided to let his inner luvvie out to play and went all theatrical, copywriting a touching little vignette of school-day tenderness to advertise "I Love My Tissues", his team's baffling attempt to arouse feelings of attachment towards a product entirely defined by its disposability. Raef's advert could be watched without involuntary grimacing, but he'd forgotten that its purpose was not to get him a place at film school but to make money. He opted for the soft sell while his rivals chose the hard. Fatally, he had forgotten that when it comes to marketing thrust, Sir Alan is a grade-four cucumber man all the way – tofu just won't cut it.