Step 1: Buy lots of cheap pizza from a crappy $1 slice joint in the Village. Chill the pizza so it congeals.
(Step 1.5: Get the pizza home on the subway without anyone snatching it!)
Step 2: Dump slices into a bucket.
Step 3: Set up a camera so you can capture the beautiful moment. BONUS: Set up pizza boxes, including the empty pizza boxes from the crappy $1 pizza place.
Step 4: Make a video of yourself dumping the pizza on your head. Classy.
Step 5: Salvage the slices since you cleverly used a plastic tablecloth to cover your gross apartment floor.
NOTE: I found a couple other folks who filled buckets with pizza. Both of them are better videos than mine so definitely check them out!