My one joke is old and well known and helps me remember two important irregular verbs. It’s essential to know that my joke is from back in the days when soda from a machine cost ten cents. Here’s the joke:
A little boy from Mexico is visiting the U.S. He spies a soda machine, comes closer, and sees a slot that has written over it “Dime.” Happily, he leans over, puts his mouth close to the slot, and says, “Dame una Coca-Cola, por favor.”
Now, you have to know that “dime” means “tell me.” “Dame” means “give me.” I think of that little boy whenever I need to use the command form in “tu” of the verbs decir or dar.