Here's an entertaining activity for a large group that involves spending almost no money: bag decorating for Kid's Food Basket.
This organization provides meals to hungry children in the Grand Rapids area. You can help by donating decorated paper lunch bags for the volunteers to fill and hand out. Grab some lunch sacs from the grocery store and bring out the art supplies.
Perhaps you aren't as artistically skilled, but that's okay.
You can also embellish the lunch bags with: