I've been meaning to look more into building a Sidebar Gadget in Vista for a while now. I just happened to come across a post from Nikhil Kothari's blog entitled Authoring Sidebar Gadgets in C#. I don't really have the time to the follow longer, in-depth tutorials you see around and was interested to see how his Script# project allowed the use of C# when building a Gadget. Worth a closer look I think.