Loup Chante, Beijing
This is a tiny cafe/bar located in Haidian, the university district. It's pretty international as a lot of students get together there.
Twice a week (Wed, Sun) there is a live jazz band and the ambience is really cool. There's also a DJ on Friday and a latin music night on Sat.
This cafe/bar is also opened during the day, for people who want to have a coffee and read there.