What to play with each other?
race do not offerDepends on what genre of games you are interested in this case, you can offer a lot of games. Dota 2 it is an option, Far Cry 4, Dungeon of the Endless.
For RPG fans:
Neverwinter Nights
Baldur's Gate
Icewind Dale
For fans of Action-RPG in first person:
Borderlands
For fans of Action-RPG third-person:
Titan Quest
Diablo 2
Sacred 1, 2
For lovers of Action:
Resedent Ivel 5 or 6 (although, in my opinion, he loses the fifth part in the co-op)
Hunted. The Demon's Forge
For fans of turn-based strategy:
Heroes of Might & Magic 1 - 6 (Third masterpiece in this respect)
Divinity Original Sin is a good RPG. Portal 2 is pretty fun. Dead Island(reptide) - not great, but you can play. Remember what else - complement.
Splinter Cell: Chaos Theory/Splinter Cell: Conviction/Splinter Cell: Blacklist. One of the best co-op series, where the co-op is really interesting. Still of Trine (Enchanted Edition) and Trine 2: Complete Story of the great game.
The series of Splinter Cell in General is top class, I still prefer the old Splinter Cell: Pandora Tomorrow, the first of a series of games in which he played)
sniper elite v2,sniper elite nazi zombie army 1,2,dead island,dead island riptide,borderlands 1,2,