Leave it to Baltimore to have the quirkiest and best dance spot, the Lith Hall. This is the Lithuanian Hall in the pigtown neighborhood that hosts the best dance party every first Friday of the month called the "Save Your Soul" night where DJs play 50s and 60s soul tunes.
Be ready to sweat your butt off because the dance floor gets hot. You can cool off (or warm up depending on what you get) with cheap drinks ($2 shots of honey liquor and $4 bottles of Lithuanian and Eastern European beers among other choices).
The scene is mostly hipsters and young professionals, but the scene is diverse enough. You may even see John Waters as it's a regular hangout for the guy.
A few things to note: Things don't really pick up until around 10pm. If it's your first time, you'll need to become a member ($5) and it's a $5 entry fee.