Scrum is an agile way to manage a project, usually software development. Agile software development with Scrum is often perceived as a methodology; but rather than viewing Scrum as methodology, think of it as a framework for managing a process.
Scrum Deck Cards is used for estimating an size of user story. This Deck gives you the opportunity to have some fun during the meetings. Because happy moments em funny moments improves productivity.
How it works? Simple choose a card show your screen to your team mates, shake de phone and the card will be revealed. Simples as that.