Definitely - when Lily and Rajah get going with their "cat dancer" toy (hmm- wonder why they named it that) they often do midair flips. Rajah is sort of a clumsy boy too, and one time I saw him do that and land on his side instead of feet. He just looked around with a stunned look on his face, finally hopped up, and pretended he did it on purpose
A friend had a cat who somersaulted between her stove and counter wall (6"). She immediately gave it a treat, and when the cat did it again, gave it another treat. From then on, the cat would do it 'to order' (I've seen it) which is quite amazing, considering my friend is definitely not into training cats or anything else!
My cats like to chase each other.. and one often runs right at the couch, straight up the back of it, and push off to backflip around and land right ontop of Brutus for a sneak-attack! My li'l ninja cat.
The both do flips when there's a bug in the air to catch. :O
When I use that toy with the feathers on the end of the string on the end of a rod, Zane will get on his hind legs and bounce like a little kangaroo. Since he's such a fat (16 lbs.) cat, it looks really funny.