Since my childhood, I have enjoyed watching ants very much - respect their diligence, unity, order and tenacity. You can see this from several posts with the 'ant' tag at AppNee.
DesktopPlant is a very interesting and cool electric virtual planting program. It allows you to grow several common ornamental plants on your desktop to bring some vitality. They also do need you to take care carefully, just like the real flowers in life.