I am astonished at the number of people who seem to really believe you didn't get it. That's because you know me better than they do. <s>
When I used to work with John Baird in 2003, there was a woman who would emai out jokes. I would always reply, "I don't get it"...and I would offer some reply that would use the logic that Edith Bunker would use when you'd tell her a joke. Usually my replies were funnier than the original joke...there were days I had JB laughing his ass off.