Sure! Here's an example of a simple game about cartoon and movie family trees implemented as a single HTML file:
Family Tree Game
In this game, the player is shown a list of family tree names represented by text on a canvas. The player needs to click on the correct family tree name to earn a point. The score is displayed on the canvas as well. After each selection, the canvas is cleared and the updated score is shown. The game continues indefinitely.
This is just a simple example, but you can expand on it by adding more family trees, displaying visual pictograms instead of text, adding animations, or incorporating more complex gameplay mechanics.