There's a reality show on the Discovery Channel I don't often watch, but I'm glad when I catch it. It's called "Cash Cab". I like it because, unlike most reality competition shows where you have to consciously make an effort to apply and hope you get chosen, this show gets unsuspecting people to participate. You don't get the typical media-whores looking for their fifteen minutes of fame.
The concept is simple. People get in a minivan-style cab, expecting a normal cab ride. Lights start flashing and the driver/host tells them they're on a game show. If it's a set-up, the people are very convincing with their shock. They must answer questions until they reach their destination. If they miss three questions, they are booted from the cab wherever they are and win nothing. The questions start out really easy for $25. They get harder and the value goes up, first to $50, then to $100. There is also a "red light challenge" where they shout out things belonging to a certain category (the one I saw was members of the "Rat Pack"). If they get them all, it's good for $250.
If they make it all the way to their stop without missing three questions, there's a "video bonus question". They have the option of going double or nothing on it, but they must decide before they hear the question. The people I saw took it and ended up winning $1100! I like it because the questions aren't too hard, but hard enough that you can't just breeze through them. It's good-natured, candid, and fun.