Rihanna joins deadmau5, Calvin Harris and Seb Ingrosso in a charity concert at the House of Blues, benefitting the Children's Orthopaedic Center and Mark Taper-Johnny Mercer Artists Program at Children's Hospital Los Angeles. (Lifeline Live) Electronic artist and mouse head helmet wearer Deadmau5 pulled quit a nice little prank on dubstep king Skrillex at the […]