Activities, well this year George W. Bush and Jeff Corwin (the animal planet guy) came to talk. Jeff Corwin was amazing and super intelligent and his sense of humor was just awesome. Anyways... UNT does have theater, and I've even seen the student actors practicing on an early Sunday morning sword fighting. I've never seen a play, I would, but they don't really make an effort to get the word out about it.
Music concerts, a must go to of course. No excuses, find out when they are and go.
Friends here? Well I met most of my on campus friends from Chinese class and my major, which, most kids taking Chinese are in my major... So we're a pretty close group which makes life here fun. And I'm pretty sure it's the same for other majors as well, especially music, ESPECIALLY MUSIC, but the same for most artsy degrees as well. The physics/biology majors here are also very tight-nit as far as I can tell. (And the science buildings are new, awesome huh?)
Frats/Soroties, there's a few them, they have their own row of houses and are even building a new house for some new frat. They're a small-decent size on campus, not anywhere near as big as other schools such as UT or A&M, not really a frat school. But if you're into frats, you can expect to have your frat/sorority experience just as well here so no worries. :)