Windows
SDForum has these great set of events that they organize every month. The SIG leaders do a great job in inviting speakers. Since this is the Bay Area the quality of the speakers is really high. This was a great talk by Pete Smietana where he awed us with the demonstrations of his user drawn GDI controls. HIs technique is indeed impressive as the same code base is used to generate graphics on Windows Forms, print to paper as well as a web control. Now how cool is that. Check out the source code here.