Well, I still haven't figured out what the title SEX IS ZERO means, but I did like this movie better than the original. Most of the characters are back (there's even a new and improved main girl), a lot of the jokes are rehashed, very little nudity and the story is that same bizarre half funny/half depressing mixture, but for whatever reason I enjoyed this outing. I think the characters are starting to grow on me.
The dweeb from the first movie is still in school and even though he's a complete dork he has yet another superhot girlfriend! She's beautiful, has a great personality and is completely dedicated to him, but her mother hates him and wants to set her daughter up with a handsome, successful lawyer instead. The other stories revolve around the guys training for a MMA tournament and the girls training for the swimming championship...there's also a new sexy swim coach that catches the eye of the guy with the psychotic girlfriend. That story was actually funny. On the depressing side of things you have an attempted suicide, a really sad breakup scene and the even sadder accidental meeting afterwards.
Overall, a fun movie and I think the best improvement over the original was the new girl. The older girl was beautiful, but I really liked this girl's character and that added a new dynamic to the film: me actually caring what happened to the characters. One thing I did find disturbing was the repeated occurrence of guys sticking stuff up other guy's buttholes. WTF?