17. Solitary (Fox Reality Channel, 2006-2010)
Solitary confinement isn’t something most sane people would willingly subject themselves to, but, as you've realized, people will do literally anything for money. This particular series, aptly titled Solitary, offered a cash prize to whoever was able to last the longest in solitary confinement, with only a computer named Val to communicate with. Considering that Val was like the not-so-distant cousin of the evil computer GLaDOS from the Portal games, that wasn’t much consolation.
Also, as the contestants were being held in confinement, they had to compete in challenges like being quizzed on false facts and being forced to memorize a long speech, all in an effort to disorient them and get them to drop out faster. By the end of the series, the winner was whoever was crazy enough to hold out through the whole series, and instead of being committed like they should have been, they were given $50,000 and sent on their merry way home.