Rock out on your Labor Day hip-hop style during the3rd annual Hiero Day by celebrating at The Hieroglyphics‘ Hip Hop Music Festival and Block Party in Downtown Oakland from 11 am to 6 pm on Monday, September 1, 2014. The all day, all ages festival features a “Town Cup” Skateboard Competition, Performance by ShowTime Dunk: The Official Dunkers of the Golden State Warriors, Beat Swap…