Sure, here's an example of a simple game called "The Mad Cow" implemented as a single HTML file:
This game involves a "mad cow" represented by a red square that moves randomly within a canvas. The player's objective is to keep an eye on the mad cow and try to click on it as many times as possible before it reaches the edges of the canvas. This example utilizes the canvas element and JavaScript to handle the game logic. Please note that this is a basic implementation, and you can further enhance the game with added features or graphics based on your requirements.