The University of Maryland's Gamer Symphony is a large group of students (and some alumni) who play (and sing) exclusively video game music. The concerts are always fun, nostalgic, and *free*
Campus is a 20-minute walk from the College Park metro station, and there's a free shuttle to campus that you can take. There is also tons of free parking in the surface lot near the performing arts center.
This semester's lineup includes songs from:
Donkey Kong 64
Super Mario World
Shadow of the Colossus