I'm releasing a new set of widgets that I hacked together for daria.be. It's uses the free content from thefreedictionary.com. I modified the link contained within it because we had some issues with sidebars that forced multiple links into multiple lines.
With this set of widgets, you can add in to your theme's sidebar Quote of the Day, Word of the Day, Article of the Day, This Day in History, and Today's Birthday.
For WordPress Multiuser, the same instructions apply. You should put the file into /mu-plugins though.