(adsbygoogle = window.adsbygoogle || []).push({}); Ok, first of all there are secret challenges that can not be obtained by the barracks. One very popular one is STD. But there are many rumors of others that can be obtained.

1. Never Forget. Getting damaged by somebody, not killed than stabbing them in the back while hurt.
[ame="https://www.youtube.com/watch?v=CkI5eCZTqOU"]YouTube- Modern Warfare 2 - 'Never Forget' Challenge - HD[/ame]

2. Renaissance Man. Kill 3 different people with 3 different weapons in one life.
go to minute marker 2:24
[ame="https://www.youtube.com/watch?v=VJCk4HxKQCc"]YouTube- Modern Warfare 2: Skidrow - Team Deathmatch[/ame]

3. Infected. Get knifed by someone wearing the 'Infected' title. 3rd most common hidden challenge.

4. Bigger Bang. Take Revenge on someone who has just killed you by killing them by blowing them up with their own Claymore.

5. Radiation Sickness. Get Nuked.
Most common hidden challenge.

6. Living Dead. Survive a Final Stand Bleedout and get back up.

7. High Knife. Throw a knife as high as possible and get a kill.

8. 6fears7. use 7, 8, 9 killstreak rewards

9. Click Click Boom. Killing someone with C4 while you're in Last Stand

10. Sidekick. 3 kill in 1 life with a secondary.

11. STD. Knifing someone with the STD title on their callsign.
Videos above they are not mine.

12. The Edge I, II, III: Get the last kill in a match 1,15, and 30 times.

13. Loner: You have to get a 10 killstreak with no Killstreaks equipped.

If you know any more please either PM me or comment it.

<====== Rep it. Its good for you.

no its not it counts as one. and i did that to answer everyones answers in posts.

I kno it counts as one, hence the 'fail' part of it.

i know but i dont care about post count.

click click boom is in barracks, as well as the edge

Oh sorry bout that.