James Seng has put together a graphical validation similar to my request and shoutout for Captcha for MovableType on the Lazyweb. His version is available for download (and you can also see it in action on his site.) Great work, James.
Hat Tip: J to the O the S to the H
Finally, Danny Ayers wants to make this "Enable Comments Week". So, if you don't have comments enabled on your blog, implement the Captcha and enable them, damnit.