Has anyone had a "friends with benefits" develop into something more?

ok so heres the deal. just recently met this guy and we both determined that we are not ready for a commitment but of course we enjoy the obvious and its mutually great. speaking for myself, i usually freak out at the very thought of commitment...however, i think i could potentially click with this guy outside of the thing. we both agreed in the begining that we would be exclusive so i am really comfortable with the set up. i was just wondering if there was anyone out there who had a FWB that turned into more...i know its a rare case....