Need a good co-op game

[Toxik]

I've been playing with my best friends almost every night the game Sven Co-op, a Half Life mod that had a shitton of community-made maps, each having a different objective/setting, it was amazingly entertaining for the longest time, but now, we've pretty much played every downloadable map they've got.
We're looking for a new co-op game to play at night, either FPS, puzzle, anything good to keep up entertained and acting like idiots.
Any suggestions?

 

[Sharkey]

PORTAL 2

 

[Blade D_Hero]

PORTAL 2

Thatonethatonethatonethatone.

 

[Toxik]

PORTAL 2

We're 3, occasionally 4 :(

 

[jwso]

magicka, payday, killing floor

 

[ThirstyDonut]

Cry of Fear.

 

[DaivdBaekr]

We're looking for a new co-op game to play. Any suggestions?

We're 3, occasionally 4

*ahem*
I normally wouldn't recommend co-op players L4D2 because co-op doesn't really come into play in that game unless the AI Director is feeling ornery, but this custom map is an exception since it's more scripted (and, I can't stress enough, amazing).

 

[Raccoon99]

Mario Party.

 

[Astir]

The sniper elite v2 expansion looks neat

 

[Questionable Moose]

Killing Floor,

get it on one of its 230540 sales, fuck over your friends by wielding doors!
Also it has a pretty big community of mappers!

 

[Ceeddd]

Saints Row: The Third
Dungeon Defenders
Warframe
Warface

 

[VEGAN DAD]

teem fourtres too

 

[kamikaze15]

l4d2, borderlands

 

[Tomatketchup]

 

[aT. Wic']

If you are into brainless hacking your way trough hordes of monsters, try Rusty Hearts.
Free to play, available on Steam and Co-op function.

 

[Photek]

maplestory

 

[(vintage)marianos]

Darksouls, resident evil 5&6,& wow

 

[SPYderman]

Unreal 3, Army of Two, Half Life 2 DeathMatch has co-op servers that are fun to play on

 

[PsychoRealm]

Torchlight (I and II), Serious Sam (all three). Quake I.

 

[hXcjedders]

Borderlands 1/2