To get my son unhooked from his TV obsession the TV 'broke' for a few days. The first two days were not easy as this was winter time and he would ask over and over when will it be fixed.

Then suddenly he got over it and now will watch Peppa Pig when she comes on and gets bored by watching too much. Now with nice weather coming outside distractions will help.

Also I like someone's else suggestion about putting on the boring channels and telling them the kids channel must be playing something different!