A husband and wife each sell a personal item in order to buy a Christmas Gift for the other person.
Synopsis:
Pawn Shop!
Jim sells his favorite watch to buy Della some very nice clips for her hair.
We'll give you Cash!
Pawn Shop!
Della sells her long beautiful hair to buy Jim a chain for his watch.
We'll give you Cash!
The irony is that when they both give their gifts to each other neither one of them can use their gift! This is because they sold the items that went with the gift, to buy each other gifts in the first place.
What type of Irony was this an example of? Check out Storyboardthat's article on Irony!