Ron Jenkins, professor of theater, reads a Sanskrit prayer during a Sept. 11 Memorial Service in the Memorial Chapel while Jason Harris '09, left, listens. Posted 09/15/06 On Sept. 11, 2001, Marc Arena 07 was in class when his high school principal announced over the P.A. that the World Trade Center towers were struck by two planes. He and his classmates at Pelham Memorial High School in Pelham, N.Y. gathered around a radio, listening in awe. With an ear on the broadcast, and a pencil at hand, Arena wrote a poem. Bodies leaping from 61 floors. Like roaches in the…