As posted on Tribe.net:
Video games is probably a good one.
Other potential ideas are:
-"Pro" wrestling exchange - I don't follow wrestling, but there are enough obsessed fans out there to make a successful site, I think.
-Political Exchange - Buy and sell shares in Dubya, Dean, etc. Not as big of a market, in my view, but this is an election here. The ability of a web-based exchange simulation to act as a predictor of polictical outcomes would be very interesting.
-Sports - Buy and sell players /teams. A different approach to sports pools.
-Product/Fads - bet on the next big product fad
Of course, TV Shows is another (obvious) one...
Good Luck,
Mark