All the time.
I'm also writing songs aloud all of the time.
It has been awkward because, I'll be in the elevator at work, I'm the first guy here so it's deserted.
So I'll be going up, alone in the elevator and for no good reason, often unconsciously, in a sing-songy voice, I'll just start saying
"Sandra J. Dawson is a motherf***ing c***. A motherf***ing c***, she's a b****-c***-****e!
If you're in the market for a b****-c***-****e, look for Sandra Dawson at the b****-c*** STORE!"
so once the elevator door opens up and there's the building owner's wife!

x 1,000. I'm used to it being deserted in the mornings.
I also make voices, the more unlike the real me and preposterous the better, then I laugh my ass off.