Complex sentence: In 2007-2008, RMHS Singers were one of the 3 choirs selected out 50, accepted into the Eric Whitacre Festival singing a variety of Eric Whitacre pieces, including "Sleep" under the direction of Eric Whitacre himself.
Split into simpler sentences: In 2007-2008, RMHS Singers were one of the three choirs selected out of 50 accepted into the Eric Whitacre Festival. They sang a variety of Eric Whitacre pieces, including "Sleep," under the direction of Whitacre himself.