+1, I used to play random DotA pub games and got a huge kick out of the occasions when a team of strangers would click and work together. I sort of replicated that with pick-up basketball but topped out at below average. If anybody has team game recommendations like Forbidden Island I'd like to hear them.
Defense of the Ancients, originally a Warcraft custom map, now it's own game. Two teams of 5, you level up and train and try to kill the other team's base, a good game is maybe an hour. "Pub game" is short for public game, just groups of strangers matched to play online.