Get 100 frags in Deathmatch on Xbox LIVE
Set up a private game with a friend or with a boosting partner, on Level 1: Entryway. Make it for two players and a private game. Set it for unlimited score and twenty minutes. Go to where the rocket launcher spawns and sit here. Just keep telling your friend to go in that green hallway and hit him with rockets. It takes around ten minutes to get one hundred kills, then switch.