“When I was younger me and a friend used to have tons of fun creating roleplaying scenarios in MSPaint.

One would go out while the other would design a large maze filled with traps, dead ends and traps. Then he would zoom in as far as possible to the entrance of the maze and using only the scroll bars the other player would navigate the maze and fight monsters by rolling dice and comparing designed stats.

It could be equally as fun to design as to play the maze, and I believe its a great example on how we define our own games.