Sure! Here's an example of a simple game where a bouncy ball moves up and down endlessly using JavaScript and HTML. Note that this code can be placed in a single HTML file and enclosed in script tags.
In this game, the ball continuously moves up and down inside the canvas element. As it reaches the floor or the ceiling, it bounces off by reversing its vertical motion direction. The `requestAnimationFrame` method is used to create a smooth animation loop.
You can customize the appearance of the ball by modifying its properties like `radius` and `color` in the `ball` object.