Slayeroffice has come up with a number of great bookmarklets. Tonight I just noticed that they have one that combines them all. You click the bookmarklet – and then you pick which one you want to use (so instead of having 10 different favlets (for slayeroffice) you have just one but access to them all from that one. Ok, I'm overexplaining. It's really cool. There. That does it.
(some fo the favlets included in this is the mouesover DOM inspector, "remove children" (removes elements off a page so you can see how it's constructed), ruler, resize fonts… and more)