AssetHat 0.4 is now available. It’s a Rails gem that makes CSS, JS, and images load faster—especially useful for mobile websites. Beyond the usual concatenation and minification, AssetHat can rewrite CSS image URLs to use multiple CDN subdomains, and make it as simple as <%= include_js :jquery %> to load popular third-party JS from Google’s CDN. To switch on LABjs, just add :loader => :lab_js. Check out the official website, stats from a bunch of production sites, and the extensive docs for more.