Lush

This is a nice place, one of my favorites. good drinks, good food, good ambience (sometimes it gets too crowded though)
it's above the bookstore on the main crossroad at wudaokou.
They have open-mic night, quiz night, movie night, and every other night.
Most of the foreign students go here at daylight to study, then to drink and hang out at night. can't remember if they have wifi or not, but by the time i'm writing this they should have already make it available there.
they have everything from sandiwch to sisha (hookah), hot chocolate to absinth.
sometimes they run out of seats on crowded nights, be sure to get there earlier like at 8 pm, or even later like at 4am hangover. it is very often for people to stand around the bars waiting for the seats.
this place is opened for 24 hour. it has the same management with the bar club 'zub' on the same road.
the burgers and bagels are great. and they give discount for a bucket of beers.

A popular bar for foreigners located above a tiny bookstore. Its location is a bit odd. You literally enter a quiet bookstore, then walk upstairs and open a door to a small, humid, loud room packed with people. The night I was here there were so many people here that it was almost impossible to move. The live band was playing something that can only be described as a cross between a dying cat and socket wrenches spinning in a drying machine. The drinks here, although still cheap by western standards, were among the most expensive I've seen in Beijing as well.