I work at Microsoft. I generally use a Mac. I generally write in Java. Some of my code is open sourced. Indeed, it is a strange new world.
I work on the Team Foundation Server team, developing cross-platform tools for developers to target Microsoft platforms, including:
Team Explorer Everywhere
A set of development tools for Team Foundation Server, including a cross-platform command-line client, a plug-in to the Eclipse IDE, and a Java API for accessing TFS.
A tool to create local git repositories based on TFS server data.
Random other things to make version control tools better on the Microsoft platform.