Put on a car wash, but get the kids to get people to sponsor them per car before hand. i.e. each kid gets 20 people to sponsor them 10 cents per car, the group washes 100 cars, each kid collects $200! Also, people getting their car washed often insist on leaving a donation so have a “Free Donation Box” set up somewhere. The kicker is to make sure your kids collect the $ right away or they quickly lose motivation to do so. There is potential to make big $$ for your group in this one!