Complex sentence: Hayes was invited to the 2007 Youth Development Festival, a USA Basketball sponsored event for elite sophomores and juniors in high school, biennially at the U.S. Olympic Training Center.
Split into simpler sentences: Hayes was invited to the 2007 Youth Development Festival, a USA Basketball sponsored event for elite sophomores and juniors in high school. The event has been held biennially at the U.S. Olympic Training Center.