In the romantic comedy movie What's Your Number?, actor Chris Evans wears a pair of Ray-Ban RB2132 New Wayfarer sunglasses with black frame and Crystal Green lenses (color code 901). It looks like Chris Evans' sunglasses have the Polarized lenses (the "p" behind the Ray-Ban logo can just be spotted). The New Wayfarer is a slightly updated version of the original Wayfarer, one of the most popular sunglasses frames ever made. The Wayfarer can be seen in many films (see sightings here).
Get the New Wayfarer on FramesDirect, Amazon.com or BestBuyEyeglasses (and use discount coupons below). Note that polarized versions of Ray-Ban glasses is much more expensive than the non-polarized versions.
Referece: Ray-Ban RB2132 New Wayfarer Black frame / Crystal Green polarized lenses (901/58)