Check out this nice write up about build automation. In particular, note the bit about keeping tabs on code quality.
I think it’s often overlooked that “quality injection” is a huge benefit of CI. Yes, it’s all well and good that your code compiles, but that doesn’t really tell you much about the quality or give you any useful metrics you can act on.
There’s a handful of utilities out there that you can tie into your build to collect info about your codebase (checkstyle, coverity, simian, findbugs to name a few).
Point is – when you start thinking about how you can leverage your automated build to inject quality into your process, things can get really interesting.