Before he made a career out of making people laugh, Richard Pryor spend a couple of years in the United States Army. He served from 1958 to 1960 (coincidentally, he was also stationed in Germany for the exact same time period as Elvis Presley), but didn't manage to spend much time actually working. Most of Pryor's time in the Army was spent behind bars in an army prison.
The crime? It was pretty serious! After racial provocation by a white soldier, Pryor and a group of other black soldiers beat and stabbed him. The white soldier was not killed, but as you can probably imagine, he was very seriously injured. The incident didn't stop Pryor from launching an incredibly successful career as an entertainer, but there was certainly a black spot left on his record.