If anyone has a large codebase which they've just kind of thought out and coded, even if it works fine, I advise you to write out a quick explanation of how it actually works, and get a friend to read it through. Hell, post it on one of the boards here and I'm sure people would be happy to look over it and make suggestions.
Right now though, I'd like to start coding some shiny things. Most of my previous coding endeavours have either not been graphics related (see my tree generation code) or haven't been that impressive - laying the foundations of understanding things.
I'd appreciate suggestions of where I might start to branch out into cool effects. I was thinking of working on a water renderer, building it up from a simple water plane in my terrain which reflects, to refractions in a fragment program, and proper merging between refraction and reflection. Or perhaps I'd work on shadowing techniques, lightmapping, or more advanced lighting than just a simple per vertex GL light (my previous experience).
In essence, I'm looking for intermediate graphics tasks that I can start on, which will hopefully stretch my understanding of real time graphics, and also stretch the design of my code as it starts to incorporate more things, in a good and flexible way.
Unfortunately, I'm a poor student so I can't afford any GBP30 books, but if anyone has any whitepapers specifically in mind, that'd be even better. That reminds me! I have a progressive mesh whitepaper that I never got around to reading, I should take a look at that one of these days...
edit: in case you haven't guessed, I'm seeing how long I can keep up a daily update schedule.