I don't think folders, as implemented in iOS for iPhone and iPad, would work well on the TV screen.
Instead, I think categories/tabs, similar to those used at the very top of most apps, is the way to go. Or another analogy, using different screens/pages similar to the homescreens on iOS. I'd like one screen/category/tab for tv shows or movies apps, one for games, one for music apps, one for misc or not often used.