Fast Eddies which used to be called Shark Club is a pool hall but they have a downstairs that has live bands, salsa and DJ, depends on what day you go.

Ned Devines has 2 locations(Main Street & Herndon) which has live bands and DJ and also depends on what day you go.

TT Reynolds always has live bands but it's pretty tight in there.

El Lupos, I've on been there twice and it wasn't bad. They let 18 and up there so they got young bucks in there trying to get drinks all day. They make a section of the restaurant a dance floor at night.

Bungalow Billiards in Chantilly and Sterling has live bands sometimes and it's a pool hall.

Blue Iguana in Fair Lakes isn't bad, they have awesome food.

TGIF Fridays has bomb ass happy hour prices, at least the one in next to Fair Oaks.

That's all I can think of right now, my lunch is making me sleepy. I'll post more later.
PJ Skidoos has ladies night on Tuesdays and they have a DJ.

Bridges always has a DJ and they love playing hip hop over there. It's more like a pool hall but they have a little dance floor section you can get all disco inferno on.