'The Green Room with Paul Provenza' (Thu., 10:30PM ET on Showtime) pulls together a smattering of veteran comedians to discuss heated, taboo topics -- or their seedy ancestry, as is the case for Aussie Jim Jefferies.

The comedian has a distant forefather who was among the first fleet to Australia -- a ship full of criminals. But he made good: "He was one of the first people to be set free from [being one of] the convicts and actually become a citizen ... So there's a lot of [family] pride," explains Jefferies.

Then along came the Internet. An intrepid historian listed everyone's crimes on the web, and "old Georgy" wasn't such a model citizen after all.