I will joke with the clerks at the checkout counters, whether in box stores or mom and pop shops. Usually it's a historical play on the amount I have to pay, or receive in change. i.e. change of $10.66 = Battle of Hastings, $14.92 = Columbus in America, etc.
Last experience:
"That'll be $17.76."
"Ah, a famous date in history."
"Whut's that?"
"The birth of our country."
"Kewel!"
I didn't know whether to laugh or cry.
I do that with future dates:
"That'll be $20.14."
"Ah, a famous date in the future."
"Whut's that?"
"The year Obama seized power and dismissed the Congress and Senate."
"Kewel!"
Or
"That'll be $20.17."
"Ah, a famous date in the future."
"Whut's that?"
"The year death camps started operating in America to kill Christians, whites, and conservatives."
"Kewel!"