"The Joker Goes To School"
Joker captures Batman and Robin with a gimmicked vending machine, then locks them into electric chairs, which are connected to a slot machine. If three lemons come up, fifty thousand Volts of 'electrifying electricity' will be sent through the chairs. The first two are indeed lemons, and they wait breathlessly for the third!
"Horrors! One lemon! Double horrors!! Two lemons!!"
Gotham City has a power failure, shutting down the slot machine. Two policemen happen to drive by, and let the caped crusaders out.
Joker loiters on school property!