littleBits Latch

The latch allows you to turn a momentary input, like a button or a pressure sensor, into an on-off switch, like a toggle.

If you place a button in front of the latch, and a light after, pressing the button once will turn it ON and keep it ON. Pressing it again will turn it OFF. Try placing a sound trigger in front of the latch and a light after it, then, just snap your fingers!