I nominate George Alexander Trebek as a stand-up Dude. Mr Trebek has a calm demeanor and seems to be a real cool guy. He has a degree in philosophy, so he could probably teach a lot of us a few things.
It's not just because of his recent diagnosis, but it is part of it. When he announced it, he did so with an attitude that I'll admit I wouldn't have. He even made a joke saying he has to live because he's still under contract.