Mac: If you love the new "pull to refresh" gesture that seems to be sweeping the nation, you can actually add it to your browser with this simple extension.
This only works on Mac OS X Lion, due to the way scrolling works, but it does add a nice feature to Chrome that you've probably become accustomed to. It isn't in the Web Store yet, but you can grab a ZIP file with the .crx or .safariextension files over at the GitHub page, then drag it into your browser manually. Once it's installed, just scroll to the top of a page, then drag the page down to refresh it without taking your fingers off the trackpad.
Pull to Refresh is a free download for Chrome and Safari on Mac OS X Lion.