MonoGame is the little brother of Mono: a small and cool platform for making (mostly) 2D games. It’s an open source implementation of XNA and is compatible with iOS, Android, Mac, MacOS, Linux and Windows 8 (support for more platforms is coming). If however, more complex and 3D games is your thing, you can head out to Unity3D, also in the Mono family.
1. Get MonoGame from CodePlex
Download the latest MonoGame version from Codeplex. The is are multiple versions: a Windows one, a MonoDevelop one and, finally, the one we need, the Xamarin version. They each come as an .mpack, which needs to be installed in the corresponding IDE.