My mate used to work as a car park attendant, and it was fairly boring by all accounts, so he used to superglue 50p coins to the pavement by his hut and laugh at anyone trying to pick them up. A homeless guy had the last laugh though - after spending 10 minutes trying to prise it from the cement, he walked off, came back with a crow bar, and chiselled it up. My mate figured if he was that keen to get the money, he deserved it.