Las Vegas headliners can be fiercely competitive. Today Norm, our local scribe of celebrity culture, reports on the fueds between Penn Jillette (of Penn & Teller fame) and David Copperfield as well as the most recent developments in the long running battle of loathing between our town’s two Joan Rivers impersonators Frank Marino and Kenny Kerr. As Penn is one of the sharpest and cruelest jokers in town my advice to Copperfield is to roll over before he gets rolled over. Copperfield is a hapless Moby with our local Eminem heading right at him. As for Kerr and Marino, they seem to enjoy their feud even more than the rest of us and so I put in a call to Marino this morning to get the inside scoop on the latest round. Stay tuned for an update…