I cut these sheets into strips of three and rotate -- Week #1, Week #2 and Week #3. Each week's strips hang on a large dry-erase board near the stairs and the back door. This system works out nicely as we have three kids and three bathrooms. By doing it this way and rotating assignments, no one can claim that their jobs aren't fair. (You can click on each job sheet to see it clearly.)
Each day has an allowance amount fixed to it. Once all their jobs are done for that day, they have me sign it off. If they choose not to complete all their jobs, they miss out on that day's amount come payday. We also have a rule that they can't play the computer, watch TV or play with friends until their jobs are done. They have pretty big incentives to complete their work which makes it so I don't have to nag so much.
Note: I leave Saturday blank for their dad to give them assignments. I find that if he has three people to boss around on Saturday, he doesn't feel the need to give me assignements too. :)