I wouldn't - and with good reason too:
In Sacramento CA USA, a local radio competition to "hold your wee for a Wii" has ended with a Sacramento woman dead from water poisoning.
From the article:
"An Associated Press interview with another contestant, named James Ybarra, claimed that contestants were initially given eight ounce bottles of water to drink every fifteen minutes, with larger bottles being used once contestants began to drop out. According to Ybarra, 'They told us if you don't feel like you can do this, don't put your health at risk.' He described the victim as 'a nice lady' and that 'she was telling me about her family and her three kids and how she was doing it for her kids.'"