Who wants to mess with letters from morning until night? Even adults can't stomach a whole day of study. With that in mind you don't want to bombard your child to the point it becomes counter productive.
Away from the classroom, they want to have fun! They want to get back to playing games and enjoying themselves as much as they can. Don't overlook the possibilities available in educational toys. Some of them are so much fun you may not realize their value for development and learning.