Coffee In Space

One of the best jokes I've ever heard (or rather read)

"In space, how do you keep your coffee cup on the table? Velcro. How do you keep your coffee in the cup? More velcro."

Why do I find it so funny? I don't know, perhaps because it's so silly and absurd. I classify this as "funny always" per the classification introduced in Robert Heinlein's "The Moon Is a Harsh Mistress". Anybody knows where this joke comes from? I don't remember and just can't seem to find out.