http://beijinggoclub.com which meets in a hostel near dongsi (near the middle of the city) on Tuesday nights at 730pm. Check the website for the most recent meeting location.
Chun Xiu Lu north end, east side - there are sometimes old dudes sitting around out there playing.
West of JinSong bridge, turn left at the first main street, "willow" something, pass the police station. Keep going til you pass a corner restaurant with glass windows and the first floor tables visible raised up from the sidewalk. Right after that there is a little alley with a bike repair station. Turn right and then look immediately to the right - there should be a gateway leading upstairs to a club which has classes for kids, and a room with a bunch of guys playing.
Some old dudes (but good sometimes) putzing around on the stone tables near the climbing wall.
Fancy club that costs like 20 kuai / hour, in the middle south.