Fractured | Fractal Art Studio
Fractured is an awesome GPU accelerated fractal exploration application running right in your browser. It lets you zoom in to a variety of fractals and share your discoveries on Flickr and Imgur. WebGL or Nokia WebCL is required; the latter is typically slower (due to it being a browser extension rather than an integrated component), but allows for much deeper zoom levels.
Update: It turns out that Fractured currently requires an NVIDIA GPU in order to work with WebCL. Unfortunately the author is currently on vacation, so it may take a week or two to get this fixed.
You can still try the WebGL version with other systems.