In an application I'm working on at work I want to be able to display various bits of version information in the UI. This goes for both production deployments from Python EGG files and in development running straight out of the repository.
We use Mercurial for revision control so it is a logical choice for a version information source. The result of some hacking is my first Mercurial extension and commit hook.
See the README file rendered at that link for the details. Click here to download version 1.0.