Non-Linux FOSS: .NET?
No, really! While on a normal day, the word "Microsoft" can be used as an antonym for "Open", the world of .NET seems to be going legitimately open source. I have to confess that my limited development knowledge doesn't give me a full appreciation of the significance of .NET and ASP.NET things being released into the open-source world the end of last year, but seeing actual GitHub repositories of the core technologies is encouraging.
Are you a Linux developer interested in branching into .NET programming now that it's open source? Are you a .NET developer who wants to develop for non-Microsoft platforms now that it's officially supported? Do you think Microsoft has done too little too late? Whatever your take, the .NET Foundation seems to be doing more than just releasing source code; the GitHub repositories are a significant step toward a real community. Check out the wide selection of Git repositories at https://microsoft.github.io.