Talking about vending machines, there used to be snacks one in our college and when u choose ya snack e.g F2, keep the "2" pressed and the thing just keeps spinning until u let go of the number, this ofcourse drops all the food on that rack, but for some reason it only worked on one of the "rack"..but woohoo...20 chocolate bars for 35p.
On a diferent note, anyone used to use that 1 pound trick in phone booths?...put one pound in...make ya call, then just as the time runs out, press (can't remember too much this was like 10 yrs ago) #01# or something along them lines and it ejects your pound back out. You have to remember mobile phones wasn't accessible to everyone as yet (first Nokias only just came out (but was like kettle size!!), and this saved alot of cash.