I've noticed recently that I'm making a lot of annotations and corrections to Microsoft's online Win32 API documentation, and while re-reading one the other day I discovered I can view a list of all the annotations I've made.

In fact, it can be viewed publicly:
http://msdn.microsoft.com/en-us/library/user-xenonofarcticus.aspx?n=0

Recently, I've been doing some UI work. I program for Windows in C++ on bare-metal Win32 API. No MFC, no WTL, for WPF, no .NET, nothing. I frequently end up having to write my own UI widgets ("Windows Custom Controls" in Microspeak) because most control libraries assume you're using one of the above technologies. That, and most custom controls have annoying feature or performance deficiencies. So, I'm pretty good at hacking on the Win32 API.