Here are some off-beat bars that are not club scenes, but nice to hang out in for 30-ish group. Don't bother with clubs or anything with a line. There are too many good bars in town to waste time & money. Enjoy!

Sakagura -
211 E 43rd St / 3rd Ave. Sake bar & restaurant, down in the basement of an office building. They have very authentic Japanese menu (not sushi). Make reservations during weeknights. More of a restaurant than a bar.
http://www.sakagura.com/

Ginger Man -
11 E. 36th / between 5th & Madison Ave. Very nice pub. I always take my out-of-town friends here to sample the billion drafts they have. Weeknights very packed. Weekend afternoon are more relaxed. If they're packed, go to the bar across the street (forgot the name). It's owned by the same guy.
http://www.gingerman-ny.com/GingerMa...GingerMan.html

Verlaine -
110 Rivington St / Essex Street in Lower East Side. Hip lounge without the attitude. Happy hour till 10pm with pretty good martinis.
http://www.verlainenyc.com/
While you're in LES, you can just walk around. Tons of places to eat / drink in.

Mannahatta -
316 Bowery / Bleeker St. Live Jazz or musics every night. Pretty relax lounge on a weeknights. A bit too preppy during happy hours.
http://www.mannahatta.us/