Signs of Life [Steam, Official Site], an indie Early Access sci-fi survival sandbox platformer that looks pretty good has switched from XNA to MonoGame, and the developer has put up a Linux version for people to test.
See the announcement here for the full info.
You need to opt into the "monogamebeta" beta branch on Steam to access the Linux version.
Thanks for letting me know, Tchey!
About the game (Official)
Signs of Life is a sci-fi survival sandbox platformer with a combination of procedurally generated and hand-crafted content. You'll explore mysterious locations, Mine blocks for resources, and meet strange (and some familiar) creatures, some of which don't even want to kill you and eat your corpse. Along the way, you'll be able to craft armor, weapons, gadgets and more to assist you in surviving in an inhospitable environment.
About the author - Liam Dawe