cliff jumping here also
in the uk though. "this one time, at cliff jumping" we had to judge the right time to jump by throwing stones in and seeing how long they took to fall
had to time it just right to land on a wave, or you'd hit the rocks pretty hard from about 20 metres, as I found out :/
landed in about 2 metres of water and nailed my legs on the rocks, really mistimed the jump!