UW Men's Hockey!
I'm not even a UW student or alum, but I love the atmosphere of this place during a hockey game. The students are really rowdy and that chants are a mix of hilarious and incensing.
Surprisingly, the place almost never seems dirty, even near the end of a game. The bathrooms always seem relatively clean, too, which is really surprising.
The food is decent for a sports arena, if overpriced (hey, you're captive at the game, what are you gonna do?).
Considering the price of a hockey game here, it's a reasonably inexpensive and very fun way to kill an evening.