So, some options:
1) A renderer/shader framework. I've talked about this before, and always wanted to write one, but have never had the time and motivation. Maybe for once I'll get around to it.
2) Networking library. I was taking an advanced networking class this summer that got canceled half way through, so I've got a little bit of a networking framework in place. It needs massive testing, session management, and a serialization layer (I'd like to write my own for educational purposes, and not just use Boost).
3) One of my old projects. I'd still like to write a basic 3D GBA renderer and see what kind of frame rate I can manage, or perhaps expand upon the height mapping demo I had up oh so long ago (but at this point, I'd want to rewrite the entire renderer [see 1]).
4) Isometric tile engine/turn based srpg. Originally this is what I wanted to do with the height mapping demo, but I got sidetracked in model animation and 3D stuff. Of course this would have to be a small, bare-bones game, but I think a lot of it would be fun. Not only would I like to write an iso tile-based renderer, but I think a strategy game AI would be tons of fun to implement.
5) Start working on this.
At this point I'm leaning towards 1 or 4, but the problem with doing anything graphical is that I lack any shred of artistic skill, and don't know any artists who aren't busy with their own stuff. At least with the renderer I could just use the teapot or Stanford Bunny for a tech demo.
What would you like to see?
Edit: Also, I've broken the 10,000 views mark. Thanks for reading, everyone!