(adsbygoogle = window.adsbygoogle || []).push({}); I've started updating the list so that it says how to finish the challenge, not what the challenge is.
(Kill yourself and one enemy by cooking a grenade) instead of (Misery Loves Company)
I'm not finished updating it yet, but I'm working on it.
If you know a title AND how to unlock it, please tell me!

<3 – Kill yourself and one enemy by cooking a grenade
without throwing it
1bullet2kills – Kill 2 or more enemies with a single
sniper rifle bullet
1st Lt. (Levels)
1st Sgt. (Levels)
2fast – Get 15 kills using sleight of hand
Absentee Killer – Get a game winning killcam with a Sentry
Gun
Accident Prone – Fall 15 feet or more and survive
Airborne – Call in 3 Pave Lows
All Pro – Headshot 2 or more enemies with one bullet
Ambush – Kill 2 or more enemies with a single claymore 25
times
Backfire – Kill an enemy by shooting their own explosive
Backsmasher – Crush an enemy from behind with your riot
shield
Backstabber – Stab an enemyin the back
BAM! – Kill 10 enemies with cooked grenades
Barrett .50cal – Unlock all Barrett .50 cal attachments
Big Bada Boom – Kill multiple enemies with an explosive
laucher with one shot 5 times
Bite The Bullet – Get 1000 kills using Stopping Power
Blindfire – Kill an enemy while you are still dazed by a
flashbang
Bling Bling – Get 450 kills while using Bling
Blood Brothers – Win 15 Team deathmatches
Blood Money – Get 5 paybacks using headshots
Blunt Trauma – Kill 2 enemies with the riot shield melee
attack
Boilermaker – Kill 5 enemies total by destroying cars
Bombshell – Kill an bomb cattier in sabotage or search and
destroy
Boom Boom – Kill at least 2 enemies with one C4 pack 5
times
BOOM! Headshot – Get 25 headshots with an LMG
Booyah! – Kill 2 or more enemies with a single frag
grenade 5 times
Bow Down – Kill 15 enemies while crouching
Bulletproof – Deflect 1000 bullets with the riot shield
Bullseye – Stick 5 enemies with semtax grenades
C4 and After – Kill 15 enemies using C4
Catch Shrapnel – Kill 5 enemies using claymores
Charity Case – Call in 50 airdrops, using Care Packages, Sentry guns, and Emergency airdrops.
Chick Magnet – Call in 2 EMP's
Cloak and Dagger – Kill 5 enemies with throwing knives
Close Support – Get 250 killstreaks while using hardline
Companion Crate – Call in 25 Care Pckages
Completely Numb – Using painkiller, take enough damage that you would normally die.
Concussive Barrage – Kill an enemy by hitting him with a stun grenade
Counterintelligence – Get 250 close-range kills using scrambler
Crackin’ Skulls – Kill 25 enemies with headshots with an assault rifle
Darkbringer – Darkbringer (Equipment)
Deadline – Hardline Pro V (Perks)
Destroyer – Search And Destroy Victor I (Operations)
Dictator – Dictator (Precision)
Dish the Rock – Point Guard I (Basic Training)
Dishes are Done – Break The Bank (Payback)
Disruptor – Scrambler Pro I (Perks)
Double Down – Bling Pro I (Perks)
Drifter – Vandalism (Basic Training)
Dronekiller – Dronekiller (Finishing Moves)
Droppin’ Crates – Droppin’ Crates (Finishing Moves)
DZ Clear – Air-Mail I (Killstreak)
Early Detection – Bomb Prevention I (Operations)
End of Line – End Game II (Killstreak)
Enemy With Benefits – Group Hug (Precision)
Excalibur – Comando VI (Perks)
Explosive Ordinance – Search And Destroy Victor II (Operations)
Faceoff – Assault Expert I (Precision)
Finishing Touch – Finishing Touch (Finishing Moves)
Fire and Forget – Sentry Veteran II (Killstreak)
Flatliner – The Brink (Elite)
Flying Tank – 21 Ton Giant II (Killstreak)
Flyswatter – Flyswatter (Basic Training)
FNG (Levels)
Frag Out! – Grenade Kill I (Equipment)
Full Force – Danger Close I (Perks)
Full Throttle – Helicopter Inbound (Killstreak)
Get Real – Hardcore Team Player I (Operations)
Ghille in the Mist – Ghille in the Mist II (Basic Training)
Ghostrider – Air To Ground II (Killstreak)
Givin’ Static – Interference I (Killstreak)
Global Thermonuclear War – End Game I (Killstreak)
Godhand – AC130 Veteran I (Killstreak)
Grassy Knoll – Ghille in the Mist I (Basic Training)
Hands Free – Sentry Veteran I (Killstreak)
Hard Target – Airbourne (Precision)
Hard To Kill – Last Stand Pro I (Perks)
Hardcore Only – Hardcore Team Player II (Operations)
Headrush – SMG Expert I (Precision)
Heartbreaker – Scrambler Pro V (Perks)
High-Caliber – Stopping Power Pro I (Perks)
Highlander – Flawless (Precision)
Hired Gun – Counter-C4 II (Elite)
Hot Shot – Defuser I (Operations)
How The ? – How The ? (Elite)
I.C.E. Man – Counter-C4 I (Elite)
ID Thief – Identity Theft (Payback)
I’m Rich – I’m Rich I (Payback)
Impaler – Comando I (Perks)
Intergalactic – Sabotage Victor II (Operations)
Iron Lungs – Steady Aim V (Perks)
It’s Personal! – It’s Personal! (Equipment)
It’s Sabotage! – Sabotage Victor I (Operations)
Jack In The Box – Jack-in-the-Box I (Equipment)
Joint Ops – Point Guard II (Basic Training)
Juggernaut – Solid Steel II (Equipment)
Jump Jet – Vertical Takeoff I (Killstreak)
K Factor – Stopping Power Pro V (Perks)
Kill for Good – Multi-RPG II (Precision)
Kleptomaniac – Renaissance Man [Get a kill from 2 different picked up weapons] (Hidden)
Last Resort – Last Resort (Finishing Moves)
Lights Out! – Think Fast Flash (Humiliation)
Live Long… – Survivalist (Elite)
Living Dead – Living Dead [Final Stand, Get up after getting put into Final Stand] (Hidden)
Lone Wolf – Free For All Victor I (Operations)
Low Profile – Prone Shot II (Basic Training)
M4A1 – M4A1 Mastery (Primary Weapons)
Mach 5 – Mach 5 (Precision)
Mad Men – Bang For Your Buck I (Payback)
Maj. (Levels)
Martyr – Afterlife [Martyrdom, Kill someone with your Deathstreak (Hidden)
Mastermind - Claymore Shot II (Equipment)
Money Shot! - Money Shot (Payback)
NBK - NBK (Precision)
New Jack - ATM (Payback)
Ninja - Comando V (Perks)
Noob Tuber - Ouch (Humiliation)
Not in the face! - LMG Expert I (Precision)
OG - OG (Finishing Moves)
OMFG - Cruelty (Humiliation)
Omnipotent - Radar Inbound I (Killstreak)
Overwatch - Exposed I (Killstreak)
owned. - Owned (Finishing Moves)
Parting Gift - Clay-More I (Precision)
Perfectionist - Perfectionist (Precision)
Philanthropist - Special Delivery II (Killstreak)
Pin Puller - Multi-Frag II (Precision)
Pineapple Express - Grenade Kill II (Equipment)
Plastique - C4 Shot I (Equipment)
Pop Off - SMG Expert II (Precision)
Preemptive Strike - Hardline Pro I (Perks)
Pro Gambler - Airdrop Inbound II (Killstreak)
Protect and Serve - Sponge I (Primary Weapons)
Public Enemy - MVP Team Deathmatch (Operations)
Pushin’ Daisies – Goodbye (Basic Training)
Pyromaniac – Backdraft I (Basic Training)
Quickdraw - Fast Swap (Elite)
Rainmaker - Overdraft (Payback)
Re Zero - Ghille in the Mist III (Basic Training)
Reign Down – Attack Helicopter Veteran I (Killstreak)
Rejected – Backdraft II (Basic Training)
Reloaded - Scavenger Pro I (Perks)
Remote Viewer – X-Ray Vision I (Basic Training)
Rival - Rival (Humiliation)
Robin Hood - Robin Hood I (Payback)
S.S.D.D. (Levels)
Sgt. (Levels)
Share Package - Special Delivery I (Killstreak)
Shot Down – Crouch Shot I (Basic Training)
Sidekick - Sidekick - [5 kills with Secondary/Attachments/Equipment in a life] (Hidden)
SIGINT – Interference II (Killstreak)
Silence – Did you see that? (Equipment)
Skeet Shooting – Hard Landing (Humiliation)
Smash Hit – Smasher (Primary Weapons)
So Baked – Master Chef I (Elite)
Solid Steel – Solid Steel I (Equipment)
Speed Demon – Lightweight I (Perks)
Squawk Box – Attack Helicopter Veteran II (Killstreak)
Stickman – Stickman (Finishing Moves)
Streaker – Fearless (Precision)
Stuck on You – Plastered II (Equipment)
Stun Gun – Slow But Sure (Humiliation)
Submit To Authority – X-Ray Vision II (Basic Training)
Sureshot – Steady Aim I (Perks)
Surgical – The Surgical (Precision)
TacDel – Tactical Deletion (Equipment)
Ta-Da! – Jack-in-the-Box II (Equipment)
Tag! You’re it! – Hot Potato I (Humiliation)
Take A Stab – Carnie II (Equipment)
Tango Down – Prone Shot I (Basic Training)
Team Player – Team Player I (Operations)
The Anarchist – Multi-C4 II (Precision)
The Bomb – Bomb Defender I (Operations)
The Dictator- Have every bullet in an LMG clip hit an enemy
The Domino Effect – Dominoes (Elite)
The Feared – Free For All Victor II (Operations)
The Invincible – Invincible (Elite)
The Legend – Last Man Standing (Operations)
The Mad Bomber – Saboteur I (Operations)
The Mastodon – Star Player (Elite)
The Specialist (Levels)
The Watchman – Radar Inbound II (Killstreak)
Think Fast! – Think Fast (Humiliation)
Time is Money – Time Is Money I (Payback)
Time on Target – Airstrike Veteran I (Killstreak)
To The Extreme – MVP Team Hardcore (Operations)
Toxic – Radiation Sickness [Get Nuked] (Hidden)
Trackstar – Marathon Pro I (Perks)
Transformer – Transformer (Finishing Moves)
Unbelievable – Unbelievable (Finishing Moves)
Unbreakable – Unbreakable I (Primary Weapons)
Voyeur – Exposed II (Killstreak)
Wargasm- Three killstreak rewards in less than 10 seconds (thanks Valimen)

na it works like this: get a 3 different killstreaks (like UAV, counter-UAV, and predator) in 10 seconds