Darryl and Dan Culberson might possibly be the cheapest men in the world, but may also be geniuses!
The two brothers have been exchanging the same birthday card since 1973.
Daryl's birthday is in January, so every year he receives the card then. But then sends it back to his brother Dan by post for his birthday in March. It started as a joke, but now neither can stop it - as you can see the card has yellowed a little, but is still going strong!