Another great one (arguably the greatest thing I've ever done):
This summer I was in Iowa City for a wedding. The night before, some buddies (all ISU alum who were at Iowa for grad school) had gone to a party. As we were walking back to his place, we walk by another party, and the guys on the porch invite us to come up and drink, so we do. After a couple of minutes of convo, I state that we're all ISU alums, to which the guy (who had been really friendly) responds "GET OUT! WE DON'T NEED ANY ******* CYCLONES!", I argue that we're not doing anything wrong and a couple of guys agree with me, but we're outnumbered, so we leave.
This REALLY irked me, and being pretty hammered, I decided this aggression couldn't stand. So, when we get back to my friends place, we all change into ISU gear, and head back to that party. This time we're walking from the other direction. When we get there, we yell up at the porch to see if anyone is still partying, and as soon as they see us in ISU gear, a posse of about 10 guys (there were 3 of us) come out to meet us, obviously displeased.
One guy, who was obviously coked out starts screaming "those are the guys!" I immediately play dumb, and ask someone who is calmer what he's talking about. He says that about 20 minutes earlier, they kicked out a couple of guys for being ISU fans. This whole time, Coke-boy keeps screaming at me, and acting like he's gonna hit me. I ask the guy if one of them looked just like me, and then I described what I had been wearing, and the guy goes "Exactly!" I tell them that was my twin brother, and he had just come back to where we had been completely wasted, and blathering about he had gotten kicked out of a party.
Completely buying my story, the guys are ready to just let us go on our way, when Coke-head tackles me, out of nowhere. I flip him over, get him facedown, and start bashing his face into the sidewalk. This is quickly broken up, and the guy's friends start reaming him out for just attacking us, when we "weren't the guys!" The guys invite us back into the house, give us some brewskies, and Coke head's girlfriend starts cleaning up his bloody nose/face. He soon apologizes, and tells me "man, I really honestly thought you guys were these other guys we just kicked out of here..."
Stupid Hawkeyes...