Call of Duty 4: Modern Warfare/Humiliation

Humiliation Challenges are mainly killing people in ways that are hard to do, not normal ways to kill people or just killing lots of people.

Challenge	Rank Unlocked	Requirements	XP	Tactics
Airborne	42	Kill 2 enemies using bullets while in the air	250	This is very hard to do,try a shipment map with lots of people, find one person camping in a corner, jump, shoot them and keep on shooting in case someone spawns and do it like that or use Old School mode where you jump a lot higher.
Multi-Frag	42	Kill 2 or more people with a grenade	250	This is quite easy, on a team game, cook a grenade and throw it into the area enemies are in and you should get this, the 3x Frag perk (Perk 1) will help. Also use sonic Boom (Perk 2) so the grenades pack a punch, in free for all or a team game with friendly fire off, you may want to use Martyrdom (Perk 3) as well as that may help.
Carpet Bomb	42	Kill 5 enemies with one airstrike	250	Use the shipment map or a Search and Destroy game, get the airstrike, wait for everyone to spawn and fire it at the enemy spawn position, it is a bit cheap but it will get you a lot of kills.
MG Master	42	Get 5 kills with a machine-gun	250	Use a machine-gun in a map like Ambush or Downpour where lots of enemies go near, go back every time you use the gun as some people will try to kill you then get back on it, the juggernaut perk (Perk 2) might help as you get more health but it is a hard challenge to do.
Slasher	45	Kill 3 people with the knife without dying	250
Multi-C4	45	Kill 2 or more people with 1 C4	250
Hot Potato I	45	Kill 1 enemy with a thrown back grenade	50	You can throw back a grenade or you can throw a grenade to the floor then throw it again. You can also use Sonic Boom (Perk 2) to make grenades do more damage.
Hot Potato II	45	Kill 5 enemies with a thrown back grenade	100
Hot Potato III	45	Kill 15 enemies with a thrown back grenade	250	〃
Car Bomb	45	Kill 1 enemy by destroying a car	250	In free for alls, shoot cars with Light Machine-guns until they light on fire, then hope someone goes near when they explode. Grenades will help if someone is near the car as they make it explode instantly, also if you are going to use grenades, use Sonic Boom (Perk 2).
Backstabber	47	Stab an enemy in the back with the knife	250	You are probably best to go for people firing out of windows as following someone just to knife them is a very risky tactic. It may take a bit time to do this as sometimes the game doesn't recognise a back stab.
Slow But Sure	47	Kill 1 enemy while being stunned by a stun grenade	250	You can stun yourself and the enemy to do this and it is probably the best idea, even if you are lightly stunned, you still will move slowly so you might as well get fully blinded (If it is only you and the other enemy) and then aim your sights right at them and kill them, a shotgun may help.
Flashbang Veteran I	47	Kill 5 enemies dazed by a flashbang	50	If you know enemies are in a building, toss a flashbang in there then go in and kill them all, you will kill some easily.
Flashbang Veteran II	47	Kill 10 enemies dazed by a flashbang	100	〃
Flashbang Veteran III	47	Kill 25 enemies dazed by a flashbang	250	〃
Misery Loves Company I	47	Blow yourself and an enemy up with a grenade without throwing it (cooking it until it explodes)	50	Do this with people looking out of windows as they won't see you until too late, the Sonic Boom perk (Perk 2) will help as well
Misery Loves Company II	47	Blow yourself and a second enemy up with a grenade without throwing it	100	〃
Misery Loves Company III	47	Blow yourself and a third enemy up with a grenade without throwing it	250	〃
Ouch I	48	Kill 1 enemy by using a grenade launcher when the grenade hits the enemy and doesn't go off	50	Sneak up behind an enemy and use the launcher or try to aim it, it is very hard to aim as you cannot aim down the sights with grenades, so sneak up on enemies and do it
Ouch II	48	Kill 5 enemies by using a grenade launcher when the grenade hits the enemy and doesn't go off	100	〃
Ouch III	48	Kill 15 enemies by using a grenade launcher when the grenade hits the enemy and doesn't go off	250	〃
Rival	48	Kill the same person 5 times in a single match	250	For the console versions you may want to play a cage match to get this. For the computer versions you will have to play a small or 1v1 match to get this easily; you could also play a really long match which will increase your chances of getting this.
Cruelty	48	Kill an enemy with a weapon, pick up his weapon and kill him again	250	This is very easy in a small match, cage matches are good, just pick up the weapon and find them and kill them, it may take a few tries if they kill you but it should be easily done. The Juggernaut, Stopping Power or Double Tap perks (All Perk 2) might help depending on the weapon they're using
Think Fast	48	Finish off an enemy by hitting them with a frag grenade (Direct Impact)	250	Attack someone until they go to Last Stand and then throw the grenade. Some people may not have Last Stand but many people use it
Think Fast Stun	50	Finish off an enemy by hitting them with a stun grenade (Direct Impact)	250	Attack someone until they go to Last Stand and then throw the grenade. Some people may not have Last Stand but many people use it
Think Fast Flash	50	Finish off an enemy by hitting them with a flashbang (Direct Impact)	250	Attack someone until they go to Last Stand and then throw the grenade. Some people may not have Last Stand but many people use it
Return To Sender	50	Kill an enemy by shooting his C4	250	It is usually best to kill the enemy while they are throwing the C4 as they usually stay out of the way when they're going to use it
Blindfire	50	Kill an enemy while you're still dazed by a flashbang	250	You may wand to flashbang yourself and the enemy, when the flashbang goes off, fire wildly with a shotgun or machine gun and you have a good change of hitting the enemy.