Quoting j0des(+2):" I'm a mean, awful lady lol I make my son earn game time..with good behavior, using manners, sharing ... [snip!] ... But he usually still freaks lol when he hears the beep when I set a timer, he is good. Positive reinforcement is awesome!"
I don't make him earn it, but I will give him extra time if he's being really good. And if he's not listening or bullying his sister, he won't get to play on it at all.
And I find that the timer helps with getting off too. He used to pitch a fit when I said time was up, but when I did the timer today (first time we used that) he just goes "Okay, time to turn it off"