Excerpted from a letter in my inbox this morning:
A couple of weeks ago I had occasion to meet your bete noire, Mr. Bezos, at an event in Toronto celebrating the launch of Amazon's Canadian branch, Amazon.ca. I happened to be wearing a cast on my arm I decided to try and coax Jeff to sign it. I can confirm that yes, Jeff has an unpleasant laugh "a brittle, joyous yelping in panic-driven waves" (as you say). 'Cause he laughed just so while signing "Customers Rule! Jeff Bezos."
Not knowing what to do with the cast since it was removed, I tossed it up on eBay yesterday.
Get your Jeff Bezos totem here.