Mini Toons - I Don't Know It's an old joke that has been used many times, but it still made me laugh so to me it's worth more than a 2.
Maybe as a sequel you could get him to ask again but when the guy answers he says, "IDK not IDN!" Just to put that bit of individuality into it. Still a bad joke but it's less cliché than the original.
Sorry if that sounded harsh! Just my critical view.