Regarding the competition in the last post, I decided to refactor it into two categories: the shortest and the best.
The shortest valid entry was as far as I can see qwo's alert(frames);. While the toString() output usually just exposes the browser's internal classes without showing real compatibility issues, this case is actually interesting because it gives away that in some browsers, "window.frames" is just an alias for "window". Opera doesn't do this, and guess what – it does cause us real compatibility problems and we have a bug on fixing it!
BTW qwo, it could be even shorter without the semicolon 🙂 .
The entry that packed the most "real" quirks into the least code was arantius' setTimeout(alert,0). I liked the minimalness of just passing the built-in alert method directly to setTimeout() – though perhaps it would expose the same quirks and be even shorter without the '0' argument?
Congratulations, and thanks to everyone who contributed. And before I forget: the winners need to PM me their snail mail address if they want to receive the price :).