Aaron Patterson posted the slides for our talk from Rubyconf 2009.
You can grab the pdf here.
The slides are on slideshare.
The videos in the slides have been replaced with links to youtube. If you want to jump straight to the videos though, you can find them here, here, and here.

Speaking of bad ideas, if you are still interested in SexpPath, let me know. I still have never found a real use for it :)