In my spare time when not working as a software developer, I contribute to a couple open source projects that I am quite proud of:
ELMAH (Error Logging Modules and Handlers) is an application-wide error logging facility that is completely pluggable.
URL Rewriter a .NET module which mimics the Apache mod_rewrite syntax for support in IIS and Casini
Fluent Cassandra a .NET client for accessing the NoSQL Apache Cassandra database.
Oh yeah and I also wrote a book: