I've been telling people about this but I've never exaclty told them how. Here's the easiest way(you need two people to make it easier):

1) Super Sudden Death mode in special melee
2) Set your victim with a 1 handicap and you at a 9, with damage ratio at 2.0
3) Turn on bom-ombs only
4) Choose Hyrule Temple
5) Go to the bottom part(not the little platform thing but the bigger part)
6) Work up the victims damage. 500% is usually good. I find using Fox's blaster VERY useful for this part.
7) Get a bom-omb
Have the victim jump up so their body is touching the ceiling
9) Throw the bom-omb at them. They should get stuck in the ceiling

This doesnt always work. Kirby works best with this method. You can always just shatter Jigglypuff's shield. That works too. But the way I described gets the most laughs though. Your victim will sometimes move through the ceiling with their head still in it, and go flying once they reach the top.