CSS Trappist Monastery. Like the Zen Garden, but without any images (other than the "chosen twelve").
It's New Blogger, launched today at 3pm, with a retooled interface, more rounded corners, single entry archives, comments, user profiles, more template tags, mail-to-blog, knowledge, and more. (Farewell, good ol' black. We'll miss you.)
Bagophily. Extensive collection of airline sick bags.
So I guess it started when Jeremy Hedley made these buttons, dissatisfied as he was with the W3 Validator's default icons. Or was it Winer's white-on-orange button that did it, and the ensuing variations that appeared? In any case, we now have pixely buttons for just about everything, scripts to make even more, and GUI frontends to those scripts for fun and ease. And if you want to be kind to their servers; here's the source if you have Image::GD.