One of my devs recently posted about Pinterest. Unlike my girlfriends who are addicted to the act of pinning pretty images, he was instead raving about the site's "magical" CSS. Their feed has an awesome look and feel but I never stopped to wonder why. Apparently Pinterest uses jQuery Masonry (go to the site, resize your browser for the "magic").
Masonry is a dynamic grid layout plugin for jQuery. Whereas CSS floating arranges elements horizontally then vertically, Masonry arranges elements vertically, positioning each element in the next open spot in the grid. The result minimizes vertical gaps between elements of varying height, just like a mason fitting stones in a wall.
Pretty neat. I also enjoy the heavy doses of pink on the site. Obviously people who know how to design ;)