I have implemented many wonderful ideas from the homeschool book, Leadership Education by Oliver and Rachel DeMille. One of the simple ones, The Bean-Counter Game, has proved to be a fun way to encourage good behavior.
When someone does something good (anything from making their bed to Daddy quitting his job to making Why-Why smile), I tell them they can put beans in the jar. When the jar fills to the top, we are going to take a family trip to the zoo. On occasion, I'll get one of the kids to do something by bribing them with beans. It really is a lot of fun.
In the book, they recommend keeping the Bean-Counter Game light and positive. Nobody gets beans taken away for bad behavior and everyone benefits when someone gets beans because it brings everyone closer to the family activity.
(PS: I made this particular jar by cutting the vinyl letters "Create Joy" on my Cricut and placing them on a (super cheap) Ikea jar.)