Included in the package is the real life, dead tree, hold it in your hands, version of the "Concrete5 Beginners Guide" book, that I reviewed last year. It is written by Remo Laubacher, a key member of the Concrete5 community, and guides you through getting started.
This will make a great prize at a meetup soon.
If you came to the January PHP Hampshire meetup and saw Michael Cullum present "Why Open Source Is Good For You" you may have been thinking about how you can become part of an open source project.
Concrete5 may be a good place to start, it is a great CMS, which is simple to use for developers and designers. It has a welcoming community that is easy to get involved with.