Divide into teams of two or three. Each group gets a chair, a water balloon, shaving cream, and a razor. One member of the team sits in a chair — with a large water balloon on his or her head. The partner(s) cover the balloons with shaving cream, and with a single edged razor blade (just the blade) try to shave all the cream off of the balloon without breaking it. First to succeed is the winner.
Careful — if that balloon breaks, the shaving cream and water go everywhere!
You might want to have towels handy. Lots of towels.
And a tarp. A big tarp.
Shaving Cream game at youth group
P.S. — A little nick on the razor’s edge would pretty much guarantee the balloons will break.