re: What's the best practical joke you've ever played?

I installed a new faucet in our kitchen. My wife was on the sofa so I said, "look at this" and started waiving my hand in front of the faucet while turning it on and off with the other hand she couldn't see. Sightline to see me waiving and the water come on and not see me using my hand to actually turn it on was perfect. I went on and about how cool it was.

She came over to try it out, no luck. Stood there for 5m, nothing. About 2 hours later I walked by and she her walk up and waive at the sink.

Gold Jerry!