You should REALLY look into some singeplayer games.
Such as: Skyrim, Oblivion, Dragons Age, Dragon Dogma, Mirrors Edge, ALL The Lego games, Bioshock, Minecraft, Dead Space trilogy, Brothers In Arms, and Super Meat boy.
Some Mulitplayer games are:
Mass Effect Triology(Mass Effect 3 has multiplayer), Castle Crashers, and Froza(if you like racing games)
There. You will never be bored again.