Phaser HTML5 Game Framework
Phaser is a fast, fun, and desktop and mobile HTML5 framework. It comes with a host of features, so possibilities with it are nearing limitless. These features include tilemap support, audio, animation, and particles. It has a bustling community willing to help you and boasts a ton of example projects for you to learn from.
Phaser can be downloaded from their website, but it also has an online sandbox for rapid prototype creation and to learn with. While Phaser is free to download for purchase they have plugins and books to help take your development with the framework to the next level. Phaser is exactly what if claims to be, fun and fast and is a blast to work with.