ie. a joke that follows another but isnt funny.
This term was first used to label the jokes told by Simon Green but its uses are now widespread.
Someone else: Talking about that matter, what about your mum last night!
Other people in that group: That's such a lame Simon Joke.
Simon: yeah, with your mother! for a one night stand!
a long silence where everyone looks anywhere but at Simon.
Person: so you went alone to a movie