CSS Zen Garden
I was a huge fan of the CSS Zen Garden, and was so excited to have my submission accepted back in 2006 (#106!) when I was first starting out.Generally, it was a great demonstration of CSS at a time when CSS was rather novel, and the "separation of content and presentation" sticks with me today, and forms a good foundation for things like built-once responsive web design.For me personally, I met a lot of interesting people through CSSZG, including Bill Zeller (RIP[1]) and others.[1] https://news.ycombinator.com/item?id=2074109