Bookmarklets are so cool! These are little javascript links that you add to your bookmarks, which do some really cool things. I have one that tells me what a page’s weight is (how big the overall download is…very important when you work for a big company like Bell who has an no pages above 80k rule), and one that re-sizes my browsers to 800×600. They’re wicked awesome, go download some now!
Check out Bookmarklets.com for more bookmarklets, or do a Google search for bookmarklets.