-striped bg-image + howto for fitting it with your screen res.
-some firefox 4 style sheets for stylish addon
and, as a gimmick:
linux in a browser :) http://bellard.org/jslinux/
works better in firefox than in chorme (as twice as fast)
written by the legendary Fabrice Bellard http://en.wikipedia.org/wiki/Fabrice_Bellard