There's a Zenoss/Puppet integration here: http://github.com/mamba/puppet-zenoss/tree/master

Bias alert, I'm the Zenoss Community Manager.

Zenoss was written with the intention of making it easy to monitor and manage tens of thousands of network devices remotely. By using templates and device classes, once you have a single machine monitored the way you like, you can apply that to thousands of other devices, making individual changes as necessary. Zenoss handles network hardware, servers (Linux, Unix and Windows), databases, applications and just about anything else you need to monitor. There's a network map and a Google map mashup for mapping. No need to start from scratch, there's already an Open Source (GPLv2) Python-based solution with a large community and installers for Linux and OSX and a VMware image to get started (plus source for everything else). Lots of documentation and frequent releases, with commercial support available. If you're coming from Nagios or Cactii, you can reuse any custom plugins you've developed.

I'm the Community Manager for Zenoss, an open source enterprise network monitoring application. We have thousands of installations and even more users, and we see a lot of the same participation percentages seen by Linux and Wikipedia. There's a great article call Participation Inequality, pointing out that about 90% of users are never heard from again and 10% participate in forums, mailing lists and other indirect ways. We see similar numbers ourselves, and we get really great contributions from hundreds of users from enterprise IT staffs. Extensions, patches, testing and documentation are all provided by our community, you just have to work with them to lower the barriers to entry.

Sports. Tell me how I can get live HD sports and I'm listening. Everything else can get downloaded, ripped or scraped from another source.