I'm a second year university student who enjoys exploring, mostly using the Windows API with C++, and learning what all I can do. Other particular interests are learning how to make good use of new C++ features, template metaprogramming, and understanding how Boost.Preprocessor works.
I love playing around with things, so most things I make are smaller applications that do "neat" things I recently find out about or that stoop to any level to abuse C++ syntax to make it look like something else for fun.
For learning parts of the Windows API, I mainly pick a new topic and create some programs that use it. Or I decide I want to do something (recently detect double clicks on the background of Explorer windows and the desktop) and learn how to do it. Of course I can't say books didn't help as well. Charles Petzold's book was an amazing introduction.
While most of my graphical knowledge is with GDI, I have plans to go through Direct3D in more detail than I have and I might end up with a couple of games and a half-decent wrapper from doing it. Or I might move on to OpenGL. Another area I find particularly interesting is security. While I can't say that I have developed the area a lot, any research and programming I did do was extremely fun.