What's the deal with gigantic mirrored sunglsses??

[Spaded]

When I'm walking around UCSD I see these guys with humongous mirrored sunglasses (aviators?) like they're porn stars from the 1970s or something. Here's a link to a styrofoam head wearing a pair with gold rims. What is this from? Some recent movie or something? A frat, perhaps? Some retro craze? Some east coast fashion that has just arrived out west? I'm lost.