I'm not sure this would work for your kids, but for my younger kids (DS5 and DS3), we almost don't need rules because we pretty much just don't do it. For the Wii, in which they have the most interest in, they can't play Wii because its daddy's Wii. They can only play with Daddy when daddy wants to and they pretty much know that daddy would rather play outside then play Wii. They don't really ask anymore. We do allow for 30 minutes of either computer or TV time at night if time permitting. In the summer, we have been outside playing so much that time often does not permit.
They get most of their TV time when my mom babysits.
