I get a lot of questions about Open Source both as a concept and on specific Open Source projects. The Mono project which is an Open Source project that is creating a C# compiler and Common Language Reference environment. Recently Miguel de Icaza, VP Development Platform at Novell and co-founder of Ximian, was on the Microsoft campus and sat down for an interview with the people at Port 25 (a community project of the Microsoft Open Source Laboratory). The resulting interview can be viewed here.
Mono runs on Linux by the way. In the interview Miguel talks about the how and why they did Mono and their place in the Open Source community. This is one of several interviews (available here) with people involved in different language developments, including Ruby, who were at the recent LANG .NET conference held at Microsoft. These interviews are an interesting way to learn about some important computer science concepts like virtual engines.