One goal was writing a .plx loader. That's pretty much a solved problem.

Another was writing a small game, like a Lunar Lander clone. I kind of stopped aiming for this because I can't find a graphics library that doesn't get really involved really fast. All I really need is the ability to render a sprite and some terrain (which could also be an image - not procedurally generated). I've looked into SDL, OpenGL, Cairo, and a few others I can't recall. I dunno - it's been a few months since I dug into it last and maybe I could try again. GTK+ and Canvas is an option, but that's not really what it's for. There aren't a lot of Cairo demos/examples/tutorials that are game related.