The actor dons his hard hat for a tour of his eco-friendly housing project in New Orleans. Plus: Hayden Panettiere, Joel Madden and more

WHAT HAPPENS IN VEGAS…

...Stays in New York! Though Cameron Diaz enjoyed a cozy weekend with John Mayer, she happily reports to work Monday on the set of her new movie What Happens in Vegas…, which is filming in the Big Apple.