Microsoft began publishing games relatively shortly after its formation, releasing Microsoft Adventure and Microsoft Flight Simulator 1.0 in 1982. In 1995 it formally set up the Entertainment Business Unit to formally pursue games as a business, developing games in-house, acquiring companies (such as the acquisition of Electric Gravity, whose software became the basis for the Zone.com matchmaking service) and studios (Ensemble, Digital Anvil, Rare, and Bungie just to name a few), and publishing third-party games. The games ran the gamut from flight simulators, to pack-in titles for Windows, to action games, real-time strategy games, massively-multiplayer games such as Fighter Ace, UltraCorps, Asheron's Call, and Allegiance (the latter in conjunction with Microsoft Research).
With the launch of the Xbox gaming platform, Microsoft formally rebranded its gaming efforts under the name Microsoft Game Studio, or MGS. The console business has come to dwarf the PC focus of the company, particularly with the launch of the Xbox 360, but Microsoft is still releasing titles for the PC.