Fog Creek gave us a couple of months to work on something "new" for the company. After a ton of brainstorming, we came up with an idea kind of like JS fiddle for CSS, but with instant hosting baked-in. The result is http://webputty.net
WebPutty is built on Google AppEngine (a first for Fog Creek) using Python with Flask and Jinja2.
We'd love to hear what you think and if you find it useful!