I'm kind of a CSS buff. Most people, including myself, were excited that CSS3 brought new possibilities for drawing shapes like buttons, tooltips, ribbons etc.
I was tinkering on day with CSS, trying to create some googlemaps-like pins from only 1 HTML element, but my mind was on that Adidas Originals t-shirt I saw on TV, and the idea popped into my head. The firs render of the logo sucked, but by the time I got to the Nike logo, I realized that CSS has some hidden (from me) power.
I like puzzles, so working in vector software to emulate the "powers" of CSS3, was a pretty fun project. I'm glad so many people enjoyed it.
I'm very horonerd to be mentioned by so many important and diverse websites, here are some of them: