http://ajax-gist.com/
I built this on Saturday night as part of the infrastructure that will be used in the new version of ReadMyCode.org
I warmly welcome any feedback or bug reports, either in comments here or via email: aaron@aarongough.com
The code for the service is open-source and is designed to be run with zero setup on Heroku. So if you need access to a service that can support a higher load level simply launch your own version in less than 5 minutes!
http://github.com/aarongough/ajax-gist