Armpit Fudge - Boys will love it for the sheer gross factor! This will make a fun Cub Scout den activity.
Keep Your Kids Busy On $10 Or Less With These 36 Awesome Summer Activities
Cub Scout tape ball activity
cub scout crafts - Google Search
Boys and rockets are a great combination. Learn how to build & launch a rocket using 35mm film containers, Alka-Seltzers & water. Great Cub Scout activity.
A cooperative activity that promotes including everyone. Lots of modeling & discussion would make this great for building community.
I have a feeling that Cub Scouts everywhere will want to do this! @Terri Jones
homemade catapult for the Girl Scouts Entertainment Technology Junior badge
David and goliath
DIY Craft Stick Catapults -- 29 clever crafts for kids that adults will actually enjoy doing, too!