The Milky Way Lounge and Lanes, Boston
This place is fun...Saturday nights are for Salsa, Sunday nights are for karaoke, weeknights are for live music, and every night is for bowling, pool, eating, and drinking.
The Cactus Juice Margarita's are great, the food is more than edible, the beers are cheap (wicked cheap for a transplanted New Yorker), and the people are laid-back and fun.
ID is checked at the door. If you want to start out the evening with a more formal dinner, there's a restaurant (Bella Luna) above The MW, and around the corner has a couple more places to eat.
Dress Code: I've seen everything here. It's JP, so it's a little less conservative than your average Boston watering hole. (read: not quite as many baseball caps here.) It's in the basement, so it's not too dressy. Be comfortable, and don't be smelly...add a little color and fun and you'll be fine.