The PLEAC codebase was new to me. It reminds me of the idiomatic python reference (http://python.net/~goodger/projects/pycon/2007/idiomatic/han...) I've found very useful, but haven't delved into PLEAC to see if the coding examples are truly idiomatic.
Python > http://pleac.sourceforge.net/pleac_python/index.html
Ruby > http://pleac.sourceforge.net/pleac_ruby/index.html
Coverage varies depending on the language.