O2 Yoga generally has a 7pm or 7:30pm yoga class. http://www.o2yoga.com/ (http://www.o2yoga.com/). "Up dogs, down dogs, no dogma." It's vinyasa style, vigorous and quick but not hot. It's on the corner of Highland and Cedar.

Baron Baptiste in Porter Square is popular too. I've only been once, and it was hotter and more aggressive than I like, but certainly not a cult. A bit preachy, maybe, but more in that physical trainer kind of way.