1. There are definately things to do around campus. You can check out the BroncoEvents calendar to get an idea of some of the activities:
http://dsa.csupomona.edu/scis/broncoevents.asp.
2. I will let some of the other students answer that. I do know that the Greeks will have parties.
3. About 1000 students are involved in the Greek system (.5%). So it isn't huge, but there is definately a presence. I know several Greeks and they enjoy it.
4. The campus is safe. We have a lot of the same issues that other schools have. Because we have a high communter population, auto theft has been a problem. The police do patrols to try and counter this, but there are also things you can do to reduce your risk.