I recently interviewed someone that another coworker knew from his church. He sent me a thank you and one to the CW he knew. I was "best regards" the other CW was "In His Matchless Name" - WUT. That was a new one.
I work in a school, not an office, but a certain colleague has her auto-sig set to "For the kids!" and her name. It looks really silly when she's email a suggestion for staff night out or ordering pizza for lunch.