My stepdad is supposedly related to Walt Whitman. He's also a guitarist for Blood, Sweat, and Tears who has also toured with Meatloaf, Pieces of a Dream, and some others I'm not remembering at the moment.
My half brother (on my biological dad's side) is a photographer and producer in LA, but I don't think he's very well-known. Right now he directs and shoots commercials and music videos... not sure whether he's ever considered movies.
Other than that, my family's pretty average!