I've been on a few in my 'career'. Started off in 1986 on 'Bobs Full House' (who remembers that?!) and won £100. Went on to 'Telly Addicts' with my wife, dad and brother and we were knocked out in the semi final by the ladies who won. We got some videos and a sweat shirt for that. Then followed 15-1 where I came 5th in my heat and then The Crystal Maze with Richard O'Brien...what a brilliant 2 days! Didn't win, but everyone gets a crystal to take home. In 2003 I did 'Test the Nation:The Great British Quiz' and I was on the Truckers 'team'. Though we din't win as a team, I was the studio winner out of about 200 people with a score of 63 out of 70. Got a nice glass trophy. If I hadn't been working the next morning, I wouldn't have had to buy a drink all night as all the other truckers were really pleased that I'd beaten the likes of Accountants! Final show to date was Pointless in Nov 2012 when my brother and I were the first to win a £20,000 jackpot. I must say that we were very lucky that the 'right' questions came up.
To those thinking of having a go, go for it. You won't be as nervous as you might think. Once you get going, you forget about the cameras and stuff. Everyone is there to make a good TV programme, so the production staff will help you...they don't want you looking an idiot!