I know of a fed that used to run his own heating and air conditioning company out of his cubicle. He took the day off whenever he had a job. This was about 20 years ago.
Yep... Had a friend who, in 1982, had two different typists, each running their own little side business from their office... One ran a maid/house cleaning service... The other was a DC real estate saleswoman... When he tried to make them stop and threatened to fire them, he recieved a reprimand and they were promoted to another part of the agency...