Call of Duty 4 introduces the concept of “challenges” into the series, having you perform certain tasks or do something multiple times in order to get a reward or unlock something in the game.

Looking at the logs, it seems that many people are looking for details on the humiliation challenges in CoD4.

- AirBourne -

XP: 250 Points

Unlocked Level: 42
Get a 2 kill streak with bullets in midair
- Multi-Frag -

XP: 250 Points

Unlocked Level: 42

Kill at least 2 enemies with a frag grenade
- CarpetBomb -

XP earned: 250 Points

Unlocked level: 42

Kill 5 enemies with a single airstrike
- MG Master -

XP earned: 250 Points

Unlocked level: 42

Get a 5 kill streak while mounted on a machine gun

- Slasher -

XP earned: 250 Points

Unlocked level: 45

Get a 3 melee kill streak without dying

- Multi-C4 -

XP earned: 250 Points

Unlocked level: 45

Kill 2 enemies or more with a single C4 pack

- Hot Potato I -

XP earned: 50 Points

Unlocked level: 45

Kill 1 enemy with a thrown back grenade

- Hot Potato II -

XP earned: 100 Points

Unlocked level: 45

Kill 5 enemy with a thrown back grenade.