Probably senior year.  The PHS Choir was doing a Christmas performance in the auditorium, and they all entered from the back doors, holding battery operated candles and singing while walking slowly down the isles to the stage.  After pre-arranging it, I stuck my leg out into the isle as Dan Udall was walking by and he tripped and went down to his knees.  It got a good laugh from those that saw it, but Dan said that he got in trouble with the choir director (Mr. Barker?) afterwards.