Black

Alternates
HQ6G-ZP3B-C5LE-WMXA
EG4P-ZGUJ-6SQJ-3X68
6DEG-7W3X-RKJF-TDF4 3K67-9J5G-NSQH-G49M
3ZEQ-JXH9-TR2H-Y87D

Unlockable (Clearing Modes)
Silver Weapons ... Clear the game on normal or hard and the weapons will be silver with unlimited ammo. Black Ops Difficulty ... Clear all stages on hard difficulty.

M16A2 ... Clear the game on BlackOps for an M16 w/ URGL attachment.

Unlockable MSAW
Use 5SQQ-STHA-ZFFV-7XEV a profile name (new profile). Note there must be a dash between each set of alphanumerics. Once you confirm the profile name, the game will ask for a second (real) profile name. This code lets you have an MSAW in place of your side arm.

Alternates ... HQ6G-ZP3B-C5LE-WMXA and EG4P-ZGUJ-6SQJ-3X68.

Check image
Hint: Cursor ColourPlay the coloured game and pay attention to your reticule. When it shifts colour from white to another colour, you are targeting something interesting:

Red is hostile target.
Blue is a destructable secondary objective.
Black is destructable environment.
Green is a friendly (rare).