Well, I'm embarrassed to admit that I really enjoyed this silly movie. I hadn't intended to see it, but got pushed into watching it with my family. And I liked it better than they did! It was actually very sweet.
The plot, of course, is a cliche. Nerdy sorority is made cool by an ex-bunny. Not original. But it isn't meant to be. This whole thing is just a wonderful frame for the comedic talents of the people involved. We particularly enjoyed the scene where Shelley tries to act like Marilyn Monroe over the steam vent, and gets her knees badly steamed. That is just so silly that you have to laugh.
Also, at my house, we just find it so strange that the series "the girls next door," whose performers are in this film (the Faris role, Shelley, is supposed to be living at the Playboy Mansion as the movie opens), is one of the sweetest shows on TV. We expected trash, and were confounded by pleasant people that we genuinely like. So that predisposed us to like this film, too. There is a certain innocence to the whole thing.
So, I find myself in the position of recommending this film to anyone who enjoys silly comedy.