If you have Steam, pretty much the entire "Free to play" section is multiplayer. There are some good titles around there, such as the popular Team Fortress 2, and they are certainly going to add more in the future.
You can also try League of Legends, for example, but it may fall into the "over played shit" you mentioned.
But tell me, which kind of game do you want to play? Do you want an MMORPG, any game that's not an MMORPG, a shooter, or anything at all? Because we could search for interesting games if we know what you're after.
