I looked through several of the samples in the report designer's samples directory and found them a bit lacking. Several of them didn't run without changing the definition of datasources and they don't really demonstrate any features.
I went out to the SF site and found the "demo" zip for the classic engine. It has a handful of .report files in it, but opening any of them in the report designer simply yields a blank structure.
The pages on wiki.pentaho.org under the Reporting category (http://wiki.pentaho.org/display/PRPT/Home) are mostly empty, many of them just have the string "xml file for page content." as the content of the page.
Is there some other site or repository of documentation and examples for the reporting system included in Pentaho BI 1.6.0 GA?