If you have little kids, you’ve probably found they love to “help out” at the keyboard. I have a 1 year old who loves to sit on my lap and hit the keyboard, but the right combination of keystrokes can be paralyzing.
It starts in full screen mode and for any keystroke you type it prints a random shape and plays a random sound from the system media folder. There’s no configuration or settings, and to exit you go to File -> Exit. It’s portable, but requires .NET version 3.5 or later to run.
If you want a full featured application, this isn’t it, but if you want a tiny and simple application, SmashKey is for you.