Here is a fun tip that I found over at macresearch.org.
- Make sure you have a cool screen saver set (such as the RSS visualizer)
- Open Terminal (found in Applications/Utilities)
- Type the following:
- Look at your Desktop.
- To stop the whole thing and return your desktop to normal, bring the terminal window forward and press Control-C (or Command-.)
[Update: If you fear Terminal and the command line, check out bgscreensaver.]