Cooperative play is coming to Team Fortress 2 on August 15th! I haven't played the game in a very long time, but I may have to reinstall it just to try this out. They are calling this cooperative mode Mann Vs. Machine and it will let you and five friends battle against murderous robots. It is not going to be endless and if you end up surviving you will earn some impressive new loot. You will be defending a level against robots and mainly trying to not let them blow it up. There is a whole slew of robots for you to fight and they are:

Steel Gauntlet - A durable robot that will beat you to death with its fists.
Demoknight - He is quick and has a sword.
Bowman - The sniper-ish robot, but with a bow.
Minor League Scout - Pretty much just a robot scout, but he can stun you.
Quick Fix Medic - Just heals, no uberring.
Heavyweight Champ - Huge, strong and attacks in groups.
Uber Medic - Opposite of Quick Fix Medic.
Sydney Sniper - Shoots darts at long range.
Bomb Carrier Robots - The longer they carry the bomb the stronger they get.
Giants! - Massive robots with massive weapons, but they are slow.

There are also Sentry Busters, which run at an engineers sentry and then detonate. Sounds fun and reminds me of sappers from Orcs Must Die!, but Sentry Busters need time to arm once they to a sentry. There is also an undisclosed enemy of some kind that apparently feasts on the blood of the living and is rather large. This all looks pretty great and I love that Valve is trying add something new TF2. This all comes out on August 15th, Wednesday, and you can find plenty of extra information on it below. Lastly, watch the wonderful new video they made for Mann Vs. Machine in Source Filmmaker.
Main Website: http://www.teamfortress.com/mvm/

-Written by Sean Cargle