Before heading to open the Cannes Film Festival tomorrow with “The Great Gatsby,” Leonardo DiCaprio rubbed elbows with the art world in New York. DiCaprio partnered with Christie’s for last night’s auction, The 11th Hour, with works up for sale by 33 artists, including Banksy, Peter Beard, Urs Fischer, Richard Prince, Raymond Pettibon, Ed Ruscha and John Currin. Proceeds are going to benefit environmental and wildlife conservation through DiCaprio’s foundation.