Crate Rest ideas

Since Tuck is on crate rest for 60 days with a broken leg, I need some
ideas to make his time seem less like purgatory.
It can't be food oriented, because he will get fat while being idle.
It must be mind engaging, not physical.
If he had a thumb, I'd teach him to do puzzles, play computer games or play
with crayons, but he doesn't.

So what ingenuity can you think up to keep this puppy mentally active in
the 60 day interim?