You could turn off and unplug a monitor then four hours later touch the live and neutral pins on the mains plug and get a shock of over 400v from stored charge.
An old trick in the electronics industry was to take a small high voltage capacitor and tape the legs down on each side. Charge it up and then drop it into someone's jacket pocket ... some time later there would be the "What the ... Which one of you people with an unknown father, did that ?" scream!
M H C
taurus excreta cerebrum vincit