All I hear about Jenkins/Hudson is in the context of this drama. Does anyone else actually use it?
Amazingly for a Java app, I didn't have to touch a single XML file. Everything can be configured through the web interface. Fantastic!
Access the same data as Python for Python clients. This can be parsed into Python object as eval(urllib.urlopen("...").read()) and the resulting object tree is identical to that of JSON. However, when you do this, beware of the security implication. If you are connecting to a non-trusted Hudson, the server can send you malicious Python programs.
At the risk of speaking for somebody else, if Joel were to revisit his Joel Test I suspect using a Continuous Integration server would be added to the list.