Halo 3 custom games, and some suggestions?

Can anybody show me where and what these gametypes are? I remember once playing a game where one person sits down at the bottom and tries to laser all the people running around on a fllor of pallets above him. And does anybody know a good map for the predator gametype, I remember liking one where there was a fence box in the middle with a wire spool inside of it. Does anybody know any really fun custom games other than these.