In one of our last planning poker sessions the team was asked to give estimates for a story. Surprisingly all of the team members chose either a 100, an infinite card, or a combination of cards to express the weirdness of the story. After some explanations it came clear that we were missing an important card in our deck: the Planning Joker!
What's the meaning of the Planning Joker? - "I will not estimate this story as it is completely crazy."
If a story has a vast lack of meaning and does not contain any useful information then the Planning Joker is the right choice. An example for such a story would be "as a user I want to see all information" - whatever this means, it is not estimatable and needs clarification by the product owner.
Besides of a new meaningful expression in your poker sessions, the Planning Joker adds some healthy amount of fun to these sessions. Try to use it and see if it works for you - feedback is highly appreciated.
Thanks to Anton Morozov for the nice drawing of the Planning Joker.