I've been getting a lot of questions lately from parents who have young children who want to learn to make video games. Creating most high profile titles takes a couple of years with the efforts of potentially hundreds of people. But, how do you make a 7 year child understand the size of the task at hand?
I first tell my son that every person has things that they are good at and can become even better with practice. Making games takes many people that are each good at very different things like drawing, writing, and building. It takes them working together to create all the different parts that are needed for a game. So, focus on the part that you like best and becoming the best at it so you can help make a good game someday.
The good news is that these days there are places that even young children can start to learn how to make games. When I first played the original Zelda on the NES and began dreaming of someday making games like this myself...I had zero resources available to begin working toward that goal. Luckily, some of the games your child already owns have tools available for creating content and getting a glimpse into what it means to create games.
I suggest starting with the Wii game Boom Blox which has a very simple and fun mechanic at it's core. Take a ball and throw it at a constructed structure as many times as you need to destroy it completely. Getting the child to understand such a simple objective is easy and then you can begin to focus on the parts that make the experience fun for the player. There is an excellent article at IGN about how the tools work, but I'll focus here on the young ones using it.
A good place to start is with Remixing Levels which allows the child to take a level from the game that they have already played and make it play differently. Focus on simple things like if the level had a baseball before what was the strategy for taking it down? Now if you change it to a bomb that's thrown what is the result? Is the level easier? Harder? Is it fun in a whole new way or maybe even frustrating? Game Design is often about evaluating the pieces at your disposal and understanding what is fun about them being used together. The difficulty of a particular area can be changed drastically if a simple change is made and this is an excellent way to get the child thinking about these elements.
Create Mode is where a child can begin learning what it is to be a Level Designer. My son did this when he was younger and felt like he really accomplished something...it even named it "Kian's New Level" which he got a huge kick out of.
Start off by having them place individual pieces in the world and understanding how the "Gravity" in the level has an impact on them. Stack together different types of pieces and try out the level so the child can see what happens when different weapon types are used against it. The levels can start out extremely simple, but the tools are also here to create some pretty complex and elaborate setups. This is great for allowing the child to continue to improve while not overwhelming them in the beginning.
Once the child is a bit more comfortable with what the pieces do and how to place them...take a step back and have them begin planning a level. Have them take a piece of paper and begin writing out what they want to do in this next level. Add simple elements like how long is the timer? What thrown weapons will the player have? Will there be enemies in the area...how many? Which of the construction pieces will you focus on using. (As an additional challenge have them pick only 3 types to build a level from...this gives a look into the constraints often found in Level Design.)
Now have them begin to draw out what the level will look like. This can be a simple two dimensional drawing that shows basic shapes and how they stack together. This will force them to think about it's construction before building begins and gives a glimpse into how real levels are created in game development. They should then show this drawing and writing to someone and explain to them what they are trying to accomplish.
Now is where their first true game development experience will happen...because odds are that something on these written documents is not going to work. This is where they need to understand that making games is often about making a plan and then being able to make adjustments as frustrations come up. Depending on your child, they may want to go back and alter the writings when they find something didn't work. My son would get very frustrated and I need to work closely with him to understand why that piece won't sit on another, etc.
Once the level is completed, have them focus on what is fun about the level and what might be frustrating. What could they do to make it better? Did this level give you any ideas for creating something entirely new? The more they work with the level editor and focus on creating unique gameplay experiences, the more fun they will have.
Once the child has mastered what is available in Boom Blox, I would recommend moving them to Little Big Planet on the Playstation 3. This is a much more complex system to use but there are some great tutorials out there and it's almost limitless in what a child can create with it. Have them first focus on creating a duplication of a level they have played so they get a feel of how the elements work together. After that, the sky is the limit.
I know there is a lot of info here, but hopefully this gives parents trying to get their young children going a place to start. Feel free to ask questions here or on twitter and I'll do my best to help :)