I'm not a big fan of practical jokes, because they're rather mean-spirited. F'rinstance:
Why, Robin, you've caught me with the old.... tie a rope around my foot and tie the other end to a fire hydrant gag! A classic! You scamp!
Seriously, what the heck was that?
Although that doesn't hold a candle to this one:
Why, Robin! You crouched behind me so that when I was struck, I would lose my balance and impale myself onto this over sized tack! I'm hemorrhaging with laughter, I am! Now, would someone please summon medical help before I bleed out?
This is really unpleasant. We'll start over Monday.