In the movie The Hangover, Ken Jeong as Leslie Chow, wears a pair of John Varvatos V729 sunglasses. These John Varvatos sunglasses can be clearly seen on the movie poster with Ken Jeong.

There are several color combinations for these glasses, but the correct version (as seen in the movie) is the John Varvatos V729 with Silver frame.

Thanks to Wayne for the ID

Reference: John Varvatos V729 - Color: silver