http://web2py.com/examples/static/<xxx>/web2py_src.zip

<xxx> is the version number, e.g.:

1.67.2:
web2py_osx.zip  web2py_src.zip  web2py_win.zip

1.72.3:
web2py_osx.zip  web2py_src.zip  web2py_win.zip

1.76.5:
web2py_osx.zip  web2py_src.zip  web2py_win.zip

1.76.5b:
web2py_osx.zip  web2py_src.zip  web2py_win.zip

1.95.1:
web2py_osx.zip  web2py_src.zip  web2py_win.zip