Dokku - The smallest PaaS implementation you've ever seen

Powered by Docker, you can install Dokku on any hardware. Use it on inexpensive cloud providers. Once it's set up on a host, you can push Heroku-compatible applications to it via Git. They'll build using Heroku buildpacks and then run in isolated containers. The end result is your own, single-host version of Heroku.

Looks really nice. Don't have any use case now, though.