OK, hang on. Neutrinos don't go backwards in time, they go faster than light. Jokes about them usually displace forward actions observable via photonic, electronic or electrochemical activities such as seeing one enter a bar, or a phone ringing, or the thought process.
A: Faster than light neutrino!
A: Knock, knock.
B: Who's th... oh.
Anyhoo, jokes about faster than light things never get old.