How to sell ice cream

I was at Wicked last night, which was generally excellent. I'd highly recommend that any students out there wondering about taking it in get their tickets on the day. Got great seats in person at the box office, at about half the price they were on Ticketmaster online!... They did have one very sneaky money-making idea though. Turn off the air conditioning during the interval, let the theatre heat up for 15 minutes, and keep pedalling the ice cream throughout... rather devious that one.