(I used to love playing Spectre VR [http://en.wikipedia.org/wiki/Spectre_(video_game)] back in the day, multiplayer.. if BZFlag is too crazy, I may just try to rig up a Spectre VR network locally for my kids and me to have a few bashes...)
There's roughly two types of play: league play, and not. The former are either CTF or 1vs1. The latter are any of free-for-all, CTF, or rabbit hunt.
Head on over. It's fun.