Watch their Bullshit Show about the Second Amendment on Youtube. I used to watch the Show and I agreed with a lot of them and disagreed with others.
Penn and Teller are Libertarians, not Liberals, but I know many think the two ideologies are similar.
Some people that call themselves libertarians are more conservative, but he’s not one of them. I saw a wife swap show with his family on it and they are batshit crazy. They are raising there kids with no rules and they can learn what they want to learn for school. So, basically, they are raising self indulgent brats. He is a very rude egotistic person.
There is a LOT of overlap, more than most people realize. And most libertarians are not really orthodox in the "pure" views they claim to have.