Sure, here's an example of a simple racing game implemented as a single HTML file:
This game is a simple racing game where the player has to avoid oncoming obstacles (represented as red blocks). The player can move left and right using the arrow keys. The objective is to survive for as long as possible and earn points. Collision with an obstacle ends the game. The player's score is shown at the top left corner of the screen.
Please note that this is a basic example and can be further enhanced with additional features, graphics, and gameplay mechanics.