This was an excellent conference - I can highly recommend it if you want to challenge yourself and learn new stuff. This year's conference had quite a bit of Clojure content and an excellent closing keynote from Rich Hickey, creator of Clojure, that focused on "simplicity". There was also a keynote from computer science legend Gerald Sussman of MIT, who co-wrote the classic text SICP (Structure and Interpretation of Computer Programs).
The conference started with a day of (optional) workshops which including two Clojure workshops as well as a Cascalog workshop (a Clojure front end for Cascading / Hadoop).
Nathan Marz presented Twitter's new distributed computing system called Storm, written in Clojure, Nate Young presented his parser combinator library written in Clojure, Zach Tellman presented his framework for asynchronous event-driven programming in Clojure, David Nolen presented insights into clojure.core.match (structural pattern matching library), Jim Duey did a presentation explaining monads which was illustrated in Clojure.
Most of the Clojure/core team were in attendance too.
Overall, the conference focused heavily on functional programming, distributed computing and big data. Don't miss it in 2012!