Watch out:
rake check_manifest
will delete your following dirs
rm -r doc rm -r pkg rm -rf tmp rm -rf foo.log
this is a true joke! Also see:
http://groups.google.com/group/new-gem-generator/msg/95e383161be15f57
and
http://twitter.com/#!/zdavatz/status/36079710848942080
this is caused by hoe
http://www.ruby-forum.com/topic/1026718
Use the hoe git plugin instead.