In the much beloved vein of Fly on Desktop or the even more popular Cockroach on Desktop, Butterfly on Desktop spawns some butterflies which flap their wings lazily. They do absolutely nothing to enhance your productivity, but may mean all the world to enhance your mood... probably.
Just as with the other 'versions', you can right click on the system tray icon and add or remove butterflies. The Settings menu allows you to set them as always on top, as well as make Butterfly on Desktop launch along with Windows.
The program can support up to 50 butterflies which essentially become a screen saver, since you'll not be able to do anything else than stare at your screen. Remember to look away for twenty seconds every twenty minutes to prevent eye fatigue.
If you like fanciful and useless desktop enhancements, you might want to give this one a try. It's clearly more fanciful than Fly on desktop, albeit a bit less realistic.