I don't know about you, but my kids burn hot and cold on things, especially movies. I've discovered there are some great ways you can bring the movies and books your kids love into your school time.
My first suggestion are these sticker books. You buy the book and sticker pack and can buy booster packs afterwards. Each booster pack has about 10 stickers, and they are all numbered. These are great for number recognition, greater than/less than, and number ordering.
My next suggestion is to either buy a pack of stickers or do a quick Google image search for pictures of their current obsession. These can now be cut out and glued on (fine motor skills), and then write or dictate a story about them. I've saved images into Word documents for all of my kids' interests and will print them out from time to time for them to create stories.
From there you can move on to simple addition and subtraction using pictures of the characters for concrete math. For instance Diego found 3 baby tapirs but the mommy tapir says she is still missing 1 more baby. How many baby tapirs are there in all?
Depending on what the interest is you can incorporate science or history. One of my sons really loves "Go Diego Go," so we've studied many different animals thanks to the show. My daughter loves Bolt, and we took some time to study dogs with that.
Finding what interests your child and running with it is a great way to involve them in their learning.