Morville's Understanding Information Architecture prezi has crossed many of our screens lately, and it's a pretty fun explanation of information architecture.
I found Jakob Jochmann's critique of it (moreso of the prezi form) to be thought-provoking, but I wonder if many in the field haven't yet seen Jochmann's post. Here's an excerpt, but I encourage you to read the full post.
We hope you have as much fun exploring our Prezi...
...as we had working together on its creation. Cheers!