No never in the history of the game...
Has There Ever Been 6 Wickets In An Over?
There have been 5 taken recently by Mohammad Aamir of Pakistan vs Australia
No there wasn't a single instance still now, vass had took 4 wickets in 4 balls against bangladesh in 2003 WC.
I have never heard of such a thing
Yes Anil Kumble Of Indian Team Has Done So