Microsoft is Nintendo's second biggest competition along with Sony. As well as making computers, Microsoft also made the Xbox line of video game consoles. They are also the owners of one of the biggest IPs this century, Minecraft.
The Xbox was released in 2001 along side with the GameCube and the PlayStation 2. It had a green like interface. Before the actual Xbox was released, rumors were going around that the Xbox would feature a stripped version of Windows 2000, but apparently it didn't. The Xbox also used to have a big controller until the controller S (stands for slim) was released a year later.
The Xbox 360 was first seen at E3 2005 and later released in November that year. The controller is wireless and features two double a batteries making it bulky looking. The Xbox 360 also has avatars which are like Miis but they look different. A slim black model of the Xbox 360 called the Xbox 360 S was released in 2010 but had the same controller.
Kinect is a motion acsessory for the Xbox 360 that sits on top of your TV without a controller. It works for the old Xbox 360, but needs an extra plug in. It was released in 2011.