Set theory/Talk

I just remembered something I would absolutely love to see discussed in excrutiatingly fine detail! :-) Alternatives to Zermelo-Fraenkel set theory is a topic that has always fascinated me, but my limited mathematical skill (most of the material available on alternative theories seems to be at a graduate level -- i haven't gone beyond 1st year college mathematics) has meant I haven't found much information I could understand.

I'm especially interested in theories which allow the existence of a universal set, yet still somehow manage to get around Russell's Paradox? -- SJK