For trivia buffs, Discovery Channel's "Cash Cab" is heaven in a taxi. The idea is that unsuspecting cab passengers get into a taxi and the driver asks trivia questions. For each correct answer, players win money. It's a fun show to watch (or to participate vicariously in).
Now, you can play! Or, even better, you can play it with your class. "Cash Cab Games" is an interactive site that allows you to choose a character and then play the actual games played in the show. This would be an entertaining sponge activity for middle or high schoolers and one that I will recommend to teachers looking for something to do on a Friday afternoon.