RageQuit
Cause an opponent to quit within 30 seconds of killing them.

RageQuitter
Quit within 30 seconds of being killed.

Flag Warrior
Get the enemy's flag out of their base at least 3 times in a game

Bandwidth Grenade
Explosion sound is a very loud voice yelling "FREE HD MOVIE DOWNLOAD - USE CODE AM4Z AT AMAZON-VIDEO.COM". This prompts anyone in the room your opponent is playing in to start a 7 GB movie download, killing his latency.

Battery Drainer
Equipment that is deployed just like the power drainer. Players caught in the radius of effect will experience maximum controller vibration. Which doesn't stop. Ever.

Ejection Hammer
A special Grav Hammer. Any opponent you strike will immediately see his Xbox 360's disc tray open. The effects can be mitigated by purchasing Halo: Reach - Games on Demand™ for only 3200 MSP!

Darth Spartan
Betray a teammate

NadeStorm
Die in an explosion of 3 or more nades.

Two Birds, One Snipe
Kill at least two people with one sniper bullet.

Knives Out
Get 5 assassinations without dying.

Scrooge
Win with the most kills and least assists in a slayer game.

Short Fuse
Detonate a bomb in the first 30 seconds of an Assault game. (team medal)

Air Superiority
Down a flying aircraft while in one.

Share the Love
You were at least 50% of your opponents killed most by.

Early Bird
Kill an opponent within 10 seconds of spawn.

Altruist
Win with the least kills but most assists in a slayer game.

Pull Up A Chair
Kill an enemy upon emergence from Armor Lock.

Illusionist
Trick up to 3 people in a game with your hologram.