I had a little boy complain and throwing a fit about how it wasn't fair that sissy got to stay up later and watch a movie and on and on. Then this morning the grumpiness continued. I finally had enough and said "Fine, you want things to be fair you will get fair. I have work to do today and it's not fair for me to work and you to play so you all will work right along side me and not stop until I do. You'll eat lunch when I do, etc.". After cousins left we went to work.
They all quickly realized that they don't really want things to be fair and that it isn't going to be "fair". In the process of teaching a lesson I got all the windows cleaned, 1 roll of paper towels was used and about 1/2 - 3/4 of the window cleaner -- hopefully a lesson learned and not forgotten!