Good custom games:
-bumper cars - players with vehicles try to splatter those on foot. those and foot cannot shoot
-classic zombies - shotguns and swords
-freddy vs jason - yellow spartans start with magnum but can't shoot and run away from the freddy and jason who have brute shots but can only melee. last yellow spartan is allowed to shoot. Once the last yellow spartan dies, freddy and jason have a melee battle
I have not played Halo in forever but if I do play any Xbox games, it will probably be Halo 2 because it is one of the few games I like that has backwards compatibility.