I recently learned about a game called "Game of Life". It is a great example of cellular automation and how simple rules can result in complex patterns. Imagine some kind of life form living in a world. At each turn, they follow some simple rules to decide whether a life is alive or dead. In order to make the game more fun, I also added a Random button and a Clear button to help with placing the cells.
Simply run npm install then npm start. A webpage will show in the browser. Click the board to setup the initial state, or use Random button to randomize the board. Then click "Run" button to see the iterations.