What's needed is a demonstration of code maturing from blank canvas to just-get-something-working to various directions of "what if?" before settling on what's right for the task at hand.
We could structure our sessions with the first 30 minutes for instruction and the next hour or so as deeper presentation, show & tell, etc.
I agree this is a good approach but I do think that the emphasis has to be on how to do things 'The Lisp Way (tm).' I have found Marco Baringer's video demos <http://http://www.cl-user.net/asp/web-sites/slime-video>, <http://www.cl-user.net/asp/web-sites/ucw-video>) useful in how the lisp development process can work; I would be very interested in learning how to think in lisp -- CLOS, macros, "bottom-up, top-down" approaches, idioms, etc. Common Lisp is a general purpose language, with acute accent on 'general' so it would be great to see how different developers attack similar problems.