When you touch the screen on your computer and it makes a tiny ripple on it. There is no actual point to this its just fun to see what cool stuff you can touch on your computer.
2 people talking on Instant Messenger
Person 1: Hey man I'm so freakin bored I dont know what to do.
Person 2: Hey man I was bored about an hour ago but now I figured out how to Screen Ripple you should try it.
Person 1: Hey thanks man I'm no longer bored you rock!!!