Games: how to design a game

Several methods are available for different contexts to design a game or play, what other method better then playful with cards? Gamified game design:

Gameseeds: Game Seeds are wild free-spirited tiny creatures that you can play with, combine, hack and get inspired by to bring new characters and game ideas to life. The goal of the game is to embed the gameplay and the future players actions in the behaviour of the designed characters. Throughout the phases of the game you design a hero, a sidekick and finally… a game!
Grow-A-Game Cards
Tiltfactor is delighted to be able to share some design methods with the public. Developed as part of Values at Play, the Grow-A-Game cards are widely in use in both K-12 and University classrooms. Using Grow-A-Game, groups of people brainstorm novel game ideas which prioritize human values. While no prior game design experience is necessary, both experienced designers and those new to the field will have fun making games.
The art of game design, a steck of lenses – Companion to the acclaimed book The Art of Game Design: A Book of Lenses, this convenient deck contains 100 unique “lens cards” each featuring key questions that will make your game great, and a magnificent color illustration to help you remember each principle. The lenses span every aspect of game design – story, game mechanics, technology, aesthetics, psychology, creativity, teamwork, playtesting, and even business issues.
The Game Design Tool Kit – for classroom use, used at Stanford University
And a library ful of (educational game design) tools can be found here: Digital Game Making Environments for Learners
And many more methods do exist..