Yes, it's fun to test the wits of squirrels. I used to fish for squirrels off the back porch, using peanuts, fishing line, and a rod and reel (no hook though!). I'd cast out a peanut tied to the end of the line, and it would immediately be grabbed by a squirrel. I would then start reeling the squirrel in to see how long he'd hang on to the peanut. They didn't give up easily and they put up a terrific struggle. You could haul them right off the ground into the air and they'd still have a deathgrip on the peanut. It was hilarious. Eventually, though, the squirrel I was having the most fun with figured out how the line worked, and he would simply snip it with his teeth and rush off with the peanut. End of game.

Like you said, they're smart.

I've always had a real affection for squirrels. I don't understand the hostility they seem to arouse in so many people. Besides, they're cute.