O frabjous day! I stumbled across a website called The Phrase Finder. The site is chock-a-block with the origins of lots of interesting expressions. Starting today, I’m going to post a link to one of these explanations every week.
The phrase for this week is As Mad as a Hatter. Enjoy!
(And, yes, I realize that this post actually contains links to two phrases. The first link is just a bonus.)