I love the game Set. It’s a challenging puzzle/card game where the players attempt to find patterns amongst a group of cards. I also wanted to work on a project where I could use HTML5, so I decided to implement the game of Set. The result can be found here: http://set-game.andrewtongen.net.
It’s built using sinatra with em-websocket, and redis on the back-end. The js client is built with backbonejs and requirejs. Overall, it was a fun project and I learned a lot. You can check out the code for the project on github.