I've been wanting to use my hosts file to block access to undesirable websites, but didn't want the hassles of manually editing and updating it. Then I discovered Gas Mask, which makes it oh-so-easy to use alternate hosts files. All I had to do was launch it, add a new remote hosts file (I use http://someonewhocares.org/hosts/hosts), activate the new hosts file, and I'm done. It will update the hosts file when new versions are available, so I don't have to do anything more. And as an added bonus, I have cool gas mask icon in my menubar.