Make a race to the end

Let’s Make a Game 

If you have never made a game before, it is time to get started.

Take out a pencil and paper (or load up a drawing program like Microsoft Paint). This will take all of 15 minutes.

We are going to make what is referred to as a race-to-the-end board game. You have probably played a lot of these; the object is to get your token from one area of a game board to another. Common examples include Candyland (BGG), Chutes & Ladders, and Parcheesi (BGG). They are the easiest kind of game to design, and you’re going to make one now.

First, draw some kind of path. It can be straight or curved. All it takes is drawing a line. Now divide the path into spaces. You have now completed the first step out of four; you have defined the "Where" of the game

Second, come up with a theme or objective.  In a Race-to-the-End game, the players need to get from one end of the path to the other; this part answers the question of "Why"; why get to the other end of the board?  You are either running towards something or running away from something. What are the players represented as in the game? What is their goal? 
In the design of many games, it is often helpful to start by asking what the objective is, and a lot of rules will fall into place just from that. You’re now half way done!

Third, you need a set of rules to allow the players to travel from space to space. How do you move? The simplest way, which you’re probably familiar with, is to roll a die on your turn and move that many spaces forward. You also need to decide exactly how the game ends: do you have to land on the final space by exact count, or does the game end as soon as a player reaches or passes it?

Four, you now have something that has all the elements of a game, although it is missing one element common to many games: conflict. Games tend to be more interesting if you can affect your opponents, either by helping them or harming them. Think of ways to interact with your opponents. Does something happen when you land on the same space as them? Are there spaces you land on that let you do things to your opponents, such as move them forward or back? Can you move your opponents through other means on your turn (such as if you roll a certain result on the die)? Add at least one way to modify the standing of your opponents when it is your turn.

Congratulations! You have now made a game. It may not be a particularly good game but it is a functional game that can be played, and you made it in just a few minutes, with no tools other than a simple pencil and paper.

Ian Schreiber gives credit for developing this exercise to Brenda Brathwaite: The Easiest Game Design Exercise Ever (Really), because, he says she "noticed that there is this invisible barrier between a lot of people and game design, and created this as a way to get her students over their initial fear that they might not be able to design anything".