Object Oriented Macros (via @HNTweets) -- I'd suggest that you read this first and then go over the article, and then first you'll be like "Oh?!" and then "Ahh..." and finally, "Oooooh!".
CLI structural form editor for #clojure, inspired by INTERLISP (via @alandipert) -- Built using zippers, this is a very interesting structural editor. Go over to the gist and check out the editing session, it shows the power of zippers :). Inspired by Interlisp (hey, did you know that 1981 was 30 years ago? Right, I also freaked out).