Just when you though television couldn't sink any lower, a week of programmes under the title W**k Week is being planned. A documentary about the UK's first public masturbate-a-thon is also expected to be more of a turn off than a turn on.

The people at C4 are determined to get viewers to take a hand in their own TV entertainment. In the pipeline is a week of programmes that will feature a documentary about the UK's first "masturbate-a-thon" as part of a series of shows under the umbrella title W**k Week.

And it's not the hot weather that has turned the broadcaster's mind but a desire to build on the channel's previous Penis Week. "We feel this is exactly the type of provocative and mischievous programming that Channel 4 should be covering in the 11pm slot," says factual entertainment commissioning editor Andrew MacKenzie.

"Masturbation is something many people do but not many people talk about."

So is picking your nose, but do we really want to watch a programme featuring people with fingers up their nasal passages as part of Snot Week?

Some will point out that anything is better than watching endless hours of Big Brother on C4. Others will echo housemate Pete's oft-repeated, Tourette-inspired cry of "w**kers", an appropriate enough comment on this latest attempt at attention-grabbing by the channel.

The focus of the week will be a documentary about mass public masturbation taking place in London next month in aid of charity. A sort of Hand Relief to follow on from last weekend's Sport Relief.

Other programmes are being commissioned on the same theme as part of Masturbation Week. Presumably viewers won't be warned "not to try this at home".

Make up your own mind whether this is a serious attempt to understand solo sex or just another tacky way of getting ratings. Remember, the idea comes from the same channel that screened autopsies, described in the press blurb as getting "right under the skin to reveal the processes in life that tie us to our ultimate fate in death".

The TV watchdog dismissed more than 130 complaints about this first public autopsy in the UK for 170 years, saying the show didn't include images that were more explicit than those already seen on UK television. Those who saw the plethora of severed body parts - fake but looking realistic enough - on this week's Silent Witness on BBC1 may agree.

C4 isn't alone in thinking up apparently mad ideas for TV shows. Thankfully, TV hasn't yet found a way of emulating two cinema tricks - smell-o-vision, in which aromas were pumped into the auditorium or accessed via scratch cards, or the ploy of a horror film director who wired up cinema seats to give viewers a small electric shock at frightening moments.

Other TV ideas have been just as barmy, although most have more to do with getting publicity than anything else. The unashamedly tacky Live TV, a tabloid newspaper come to life, screened Topless Darts. The matches were played, not in a smoked-filled bar room, but under the sun on a beach in Australia. This was so the female players, all of whom had lost the top half of their bikinis, didn't get cold. For some strange reason, male topless darts never caught on.

Live TV, in its quest for something different, also screened the weather in Norwegian - a minority interest in this country, I suspect - and trampolining dwarfs.

I'm surprised they didn't introduce Naked Trampolining as well as the News Bunny, who was someone dressed as a giant floppy-eared rabbit who appeared behind the newsreader to give a thumbs-up or thumbs-down depending on whether it was good or bad news.

The idea was not adopted by other channels, perhaps because they were afraid viewers would mistake him for a politician.

But Naked News was introduced after success in the US, Australia and Canada. This had newsreaders - all women - gradually disrobing throughout the bulletin until they were fully naked.

ITV has its lapses too. It was madness to recommission Love Island after the abuse heaped on it by critics and viewers the first time. Dropping "Celebrity" from the title hasn't fooled anyone, something that's reflected in the audience figures. The first instalment was beaten in the ratings by both Big Brother and Only Fools On Horses (something of an embarrassment itself for BBC bosses who could at least excuse it by saying it was for charity).

Five's TV horrors include Touch A Truck, although it realised its mistake and consigned it to the scrapyard after just one series. Who in their right mind imagined a series in which contestants had to keep their hand on a vehicle to stay in the game would make good TV?

C4 was also the perpetrator of one of TV's craziest stunts, which wasn't even a programme but a red triangle in the corner of the screen. Its presence warned viewers that the programme contained explicit sex and violence. Rather than warn people who might be offended, it had the opposite effect of alerting those who liked a bit of smut that this was the programme for them. Viewing figures for triangle-branded shows rose and the experiment was quietly dropped after a few months.