Homestar Runner and Strong Bad Screensaver
From Homestar Runner Wiki
Homestar Runner and Strong Bad Screensavers are both available for download on homestarrunner.com via a Secret Page. These screensavers can also be obtained by downloading the themes.
If you download either screensaver and set it as your preferred one, then try to change the settings, a pop-up will appear that contains a picture of a dog and the caption "Bitbull". (This has yet to be tested on a Mac.)
