Started this idea since 2015 Halloween.
An HTML5 web app controlled by Leap Motion controller that screams, displays random scary picture and turns LEDs on when hand is detected.
LEDs are controlled by Raspberry Pi which subscribes to Pubnub channel which listens to hand detection signal from Leap Motion controller.
A short demo video:
* By the time the video was recorded, because Raspberry Pi had trouble connecting to WiFi so all LEDs weren't on when my hand was detected :(