The season finale of Bachelor Pad featured the two finalists facing the Prisoner's Dilemma. $250,000 was up for grabs. The finalists were told the rules and then sent to separate rooms: If they both chose to keep it, then they got nothing, and the money went to the other participants in the show. If one chose to keep, and the other chose to share, then the "keeper" got it all. If they both chose to share, then they'd split the money evenly. I'm not going to post the answer because it's pretty suspenseful and well worth watching.
(I learned from an Alan Moore comic that your best bet is to agree to share/help each other.) Via.