Jimmy put on a tux for Monday's Costume Institute Gala, but the former SNLer isn't usually one for Hollywood parties. He demonstrated this down in Kentucky for the derby last weekend by skipping out on Friday's Stuff Magazine party for a far less swanky affair. A friend says, "His driver invited him to a fraternity party. He played beer pong until 5 a.m. with the Sigma Chi frat boys [from the University of Louisville] and flirted with sorority girls." Sounds like he had a great time, but we're sure he wasn't flirting too much. He spent the rest of the weekend with his girlfriend producer Nancy Juvonen, who was by his side on Monday night as well.