Marcus "Notch" Persson is the Swedish game developer who created Minecraft. Notch is an avid participant in game jams, events in which developers have a certain amount of time to build a game according to a given theme or set of boundaries.
For the 7DPS jam, which gave participants a week to build a first person shooter, Notch submitted Shambles. It's a crude but also kind of awesome zombie-horde shooter and it's free to play right here.