i haven't been to a ton of "big" games, but the game vs KU in 2012 when we got hosed is probably the loudest that ive heard it. Also probably the maddest i have ever heard a crowd at any ISU related event.
Yep there was a very strange feeling in the air that night, and it was abnormally hot inside Hilton which didnt help. I've made the exact same comments to people that it felt like people were just waiting for something to happen so they could start fighting. Easily the most angry crowd I can ever recall.