Upper crackage. Coin slot. Droopy drawers. Butt cleavage. Call it whatever you want, but there's something undeniably sexy about the plumber's crack. It's the only "nudity" we've ever gotten from Jessica Alba, Jessica Biel used it as an appetizer to her Powder Blue main course, and Sigourney Weaver made it iconic with her low-slung panties in Alien. Here's to low-rise jeans!