It's almost horribly cliche, but "Eye Of The Tiger" by Survivor seems to be a popular choice. I think I'd try to strive for a bit more original choice though, unless you're in a market where it hasn't been done yet. Any sports "crowd pleaser" song you hear in an arena would work - "Whoomp There It Is", "Rock And Roll Part 2" by Gary Glitter - check out the ESPN Jock Jams discs for ideas. Heck, I'd just round up about 12 or 15 songs and rotate them for some variety.