I didn't make this up, so don't complain if you think it's bad (which it is).
It was Hanukkah and the tiny village was in fear of not having any latkes because they had run out of flour. Rudi, the rabbi, was called upon to help solve the problem.
He said, "don't worry, you can substitute matzo meal for the flour and the latkes will be just as delicious!"
Sheila looks to her husband and says, "Mortey, you think it'll work?"
"Of course! Everybody knows Rudolph the Rab knows grain, dear!"
I apologize to any Jewish readers (and for that matter, any non-Jewish ones) for how bad that joke is. Happy Hannukkah anyway!