The "Oddball" Gamemode from Halo III, There would be a little white ball spawned randomly in an arena and players would have to compete to collect the Oddball. Every five seconds you are holding the Oddball, you gain a point, and the person with the most points at the end of the round wins.
Edit: Everyone would get swords or rocket launchers, and if you had the oddball, you couldn't use weapons and you were slowed down a little bit.