This unique and free screensaver pummels your PC with up to 10 simultaneous tornadoes. Although not a marvel of modern graphics, Cyclone Screensaver gets its point across, and it’s nice that the tornadoes gradually morph colors as they spin. The feature set gives you a decent deal of control over how the cyclones look and behave. You can not only decide how many tornados should appear, but you can specify particle size and complexity; movement speed; and thread priority. Before downloading this application, you should know that its rather unorthodox installation process requires you to copy an SCR file into your Windows root directory. Still, storm chasers, weather enthusiasts, and science buffs might find that this free desktop decorator suits their tastes.