I've heard rumors of a 24 hour gym on the south side of the city ... It's called "B Active" ... But that's all I know. I can't find it on google, and they only have a faceb00k for their Beijing location ... can someone please HELP!
The B active gym is off Linshiguan Lu, where the US Consulate is. It's in the middle of the two Poly Center buildings, on a small road called Shenglong Jie. You can see it on Google Maps here -
Here is the listing
Poly Center right next to the 7 11