Errr, I should have posted about this when they *announced* it, but totally forgot about it, and so the contest ended, and winners were chosen.
Anyway, the Opera Software guys held a contest to create new and innovative User JavaScript, em, scripts (the closest thing to Firefox extensions), with quite a nice reward for the winners in the two sole categories. There are a few really interesting scripts, either for its usefulness, or just for being original.
It looks like it won't be the last time they'll do this, which hopefully means the coming of the long-desired extensibility in Opera (or a least a more elegant way to find and handle what's already available).