A mailman is baffled at how to mail a letter addressed ""to the greatest drummer in the world."" So what is he supposed to do? He's gotta send it. He hoofs it back to the post office, and shows it to his boss. The boss says, ""come on man, send it to Chick Webb."" So he does. Chick Webb, the bandleader from Baltimore, sees the letter on his kitchen table and says, ""Jesus! That can't be for me. I'm good, but come on. That's gotta be for Gene Krupa."" He scribbles out his name, puts in Krupa's ad…