“Want to have a little bit of fun with your Gnome desktop?  here are a few easter eggs for you.First, hit the Alt-F2 keys together to bring up the Run Applications dialog.

Type “gegls from outer space” (sans quotes) and hit the enter key.  You should get the below game, a la space invaders.

Next, try typing “free the fish” (sans quotes) into the Run Applications box.  You’ll get Wanda on your desktop.”

Source: http://www.arsgeek.com/?p=1996