nifty existing-site-as-wireframe tool

Wirify is a pretty nifty tool for converting the page you're currently looking at into a more abstract wireframe, so you can get a better feel for the layout... here it is for Yahoo:

It's a bookmarklet. (I had a bit of trouble getting it into my bookmarks collection, I ended up manually doing a "Copy Link Address" and adding it by hand to Chrome's bookmarks.)

(Another not-entire-dissimilar but SUPER fun bookmarklet is Katamari Hack that turns any site into a little game of Katamari Damacy)