Create a Charity Box
Teach your kids the importance of giving to others by creating a box (or jar, or tin can, or anything you want) to store money for charity. You can even make it a rule that any time anyone finds change on the street or under the couch cushions, it automatically goes in the charity box.
You can set up something basic in well under ten minutes. This could be as simple as taking out an old mason jar or using an old shoebox and cutting a coin slot into the lid. If you have more than ten minutes, get your kids involved by letting them decorate the charity box however they want.