The exploding lift passenger
Not played on an apprentice, but in the same vein:
In the early 70's I worked in an office on the top floor of one of Brisbanes taller buildings (about 16 levels).
One of the guys I worked with pulled this stunt on April Fool's Day.
He arrived early, before the morning peak with a few props, and rode the lift to the top floor (our office). At 8.25 the busiest time, he called the lift, splattered mince and liver over it's walls, and placed a pair of shoes facing the door, half filled with water, and a small piece of dry ice in each, before sending it back to the Ground Level.
Apparently when the lift arrived at the ground floor, the doors opened to reveal the smoking boots and bits of exploded passenger everywhere, the desired effect was achieved.
Same guy used to take the brown paper bag his lunch was wrapped in, wet it and work it into a kind of sausage shape, pointed at both ends. This would be left in the back corner of the lift in an attempt to ensure that there was an express lift available at knock off time.
Cheers,
P