We are a few weeks into the Button System.
A The Manatee (6) is ecstatic about earning buttons. She clamors for me to send jobs her way. Z The Monkey (3.5) could care less, although he does what he's told. I don't think tv time is a big motivator to him, but I have the feeling the Wii will be a bit different. He also doesn't seem to have the more=better gene. At least not yet.
AM has graciously shared her buttons, seeing the logic in watching a show now, with her brother, as opposed to waiting until some time when there is both something she wants to watch, AND her brother is otherwise occupied. Those instances are few and far between. So we divvy up the buttons and everyone wins.
I have also decided to switch to poker chips instead of buttons. There are several reasons for this, but the most pressing is that the chips have easily-discerned denominations, thus adding basic math to the lessons learned via the reward system. (Also, who doesn't like to click poker chips around? Aesthetics is key.)
I imagine someday it will occur to them to trade and barter with the tokens ("I'll give you 2 tokens if you do my math homework!"), but we'll cross that bridge when we come to it.
To make it easier on me, I have filled a can (modgepodged with scrapbook paper, naturally) with task cards (snippets of used patterned paper, naturally) that include sweeping the kitchen, hopping on one foot, reviewing printing letters and freebies. There are even a few "Mom cleans your room" cards in there :)
And one more addition: Mommy gets a Kindle for 100 of her own buttons! Stay tuned ...