See also this Sage Days 13 project with examples and documentation.
check text part of worksheets into $SAGE_ROOT/devel/sage/primer/
quadratic forms primer would be in $SAGE_ROOT/devel/sage/primer/quadratic_forms
notebook help screen would offer button to inject any primer from $SAGE_ROOT/devel/sage/primer/ into currently running notebook
Needs to be done:
doctesting of worksheets - see trac #116
ReST <-> HTML conversion?