Why not something a bit more original than just a graphical demo? Maybe something like a web browser for these forums (or a general web browser) that displays everything via opengl in some form or other.
This would let people display maybe multiple pages on a cube (one page per side) or someone might make the background plain, but have all the images on the pages rotate or spin etc.
That way it could have eye-candy galore, and still have some practical purpose behind it.
Whilst displaying this site, you might be able to create some simple image format or tag that would pop up fancy models etc when viewing the GD (or nehe) site with the browser.
It looks like we have a healthy list of themes, so I think we should compose an active list and send it in to nehe. He can then make the final decision.
The city theme looks like a good contender but we also have a bunch of neat and original ideas (which we could use for other contests). If you have any last minute themes, propose them (a quick list would proly be best). Remember that we are all creative people so the theme should be vauge enough to accomodate. We should have a cut off date for proposals. I think if we keep proposing themes the contest proly wont get off the ground, within at least the next few months.
We should probably look at discussing things like a start date and end date. Quite a few people I've spoken to have not entered a contest because the deadline or start date was around exam time.
We could also discuss a kinda "mass donation" to nehe; ie we all donate before the start of the contest. That way the prizes become that much better.
I wouldn't assume all of us are creative. Some of us keep proposing the same theme over and over. I don't compete for the prize. I would do the contest even if it was free...
I wouldnt mind doing one without a prize for once. Just getting people to notice your work is good enough. Maybe we could just induct winning demos into a Demo Hall of Fame or something.