Basicly my boys have enjoyed anything that involved making things with their
hands.  The more tools they got to use the better.  Paint is fun also, but
be prepared for spills and other messes.  I usually had one or two parents
to aid my normal team when it came to these projects.

Give the manual projects a try.  Hand your cubs a copy of the How-To-Book,
or one of the other books (names escape me at the time), and let them make a
suggestion.  This worked wonders for me.  I did it at the begining of a den
meeting.  In five minutes they were itching to start their selected project.
Just be ready as they will alway decide on the most complicated option :)