I wouldnt' really call any restaurant I go to a "guilty pleasure" and I don't really go to college spots any more, but the old favorite is "The Steak & Egg" on Wisconsin ave in DC - it's diner food, but they only have a counter, no tables, and the kitchen is right in front of you. Good shit. The only problem is that at random times of the night 20 high school kids will show up and clog the heck out of the place.
There's also Bob & Ediths in Arlington, and my back porch, which is a good late night grilling spot, when were rowdy.