My ancestry in the U.S. goes back to 1630, New Haven, Ct. but I am unaware of anything shocking. My wife who does not know who her Grandather was on her Mom's side and has been researching her past and has discovered many interesting things including being related to many of the country's forefathers and including incest which is more common than you might believe, and it does not have to be father daughter, but could be grandfather and neice, besides families marrying into each other's families repeatedly which happened where there were small communities.
Although my tree is fleshed out more than most, I've been threatening to get a paid subscription to Ancestry.com and do a little research and see if there is anyone famous. 🙂