Pyglet. Swine (small pyglet examples)
Visual art. WebGL playground [beta] WebGL playground is a straightforward idea: type in your script and see the results. But the cool part is that the editor and the results are just on the same page and that you get a handful of features that make your life easier. No need to create multiple files (html/css/js/glsl), no need to save anything after each update, no need to switch between the editor and the browser, and no need to set up the skeleton code. All necessary things are added behind the scenes. The idea is to shorten the development cycle so you can spend more time on the creative part, trying what-if scenarios, tweaking the parameters ...