Via Mark Harrison:
WSU developed a replacement for the Windows app Paint with some help from Microsoft. The app was implemented with .NET using GDI+ and C#. What I like about these projects is viewing the source code... very cool stuff.
Paint.NET is image and photo manipulation software designed to be used on computers that run Windows XP. Paint.NET is jointly developed at Washington State University with additional help from Microsoft, and is meant to be a free replacement for the MS Paint software that comes with all Windows operating systems. The programming language used to create Paint.NET is C#, with GDI+ extensions.