Our group started in 2001 as a class at PSU taught by Ursula K. Le Guin. Several of us decided to keep meeting as an ongoing critique group. (In her critiques, Le Guin sometimes reports on the reactions of a clueless, literal-minded reader named "Buntho".)
We started as a group of writers interested in science fiction and fantasy. Some of us, however, sometimes write outside of these genres. We have agreed that we are happy to read and supportively critique any type of fiction. However, all of our members are experienced readers of science fiction and/or fantasy, and these genres remain the primary focus of our group.
Before each meeting, two or three members e-mail their work to the rest of the group. At our meeting -- held on the first Saturday of the month, at Portland State University -- we take turns to offer our reactions. The author gets a chance to respond, ask questions, etc., after everyone else has commented.