re: Best practical joke you've pulled at work

Worked at a hospital where collecting urine samples was routine. A male nurse put some apple juice in a urine sample cup and secretly placed it at the corner of the nurses station. He left for a few minutes and returned when several female nurses were at the station. He said “God I am dying of thirst!” Walked over to the urine sample cup with the apple juice and drank it down in front of the female nurses.
A few of the nurses started gagging uncontrollably until the male nurse started laughing his arse off and told them the truth about the apple juice.