[jmatt]

If you are already familiar with another lisp check out Rich introducing and discussing the language in detail:

http://blip.tv/clojure/clojure-for-lisp-programmers-part-1-1...

http://blip.tv/clojure/clojure-for-lisp-programmers-part-2-1...

transcript: http://clojure.googlegroups.com/web/clojure-for-lispers-tran...

It's not 30 minutes but it's what pushed me past using it on side projects to using it whenever possible and advocating it.