During Robb Flynn’s 50th birthday bash at the Operahouse in Oakland, CA, the Machine Head frontman covered various songs with his musician friends. Covers included: Linkin Park‘s “In The End“, Temple Of The Dog‘s “Hunger Strike“, Stevie Nicks & Tom Petty‘s “Stop Draggin’ My Heart Around”, Nine Inch Nails‘ “Head Like A Hole“, George Michael’s…