Where you lay out a load of empty 2 litre bottles in a row, place a skateboard with no wheels ontop, run and jump on it, and then roll along. It's bloody hard and can hurt like hell, but its pretty fun to do.
"Have you just been bottle skating?"
"Yeah, and I've fractured my wrist in two places."
"But it was fun, right?"
"Hell yeah!"
A game played at parties more than likely high school or college, in which two or more completely drunk dumb asses hit each other over the head with a 2 liter bottle taking turns.
"Man, my head is bleeding from that game or bottlewhap we played last night."