In Audrey Niffenegger's novel The Time Traveler's Wife, the protagonist, Henry DeTamble, time travels involuntarily. After he marries, he begins to frequently travel to various times in his wife's childhood, during which he befriends her, which leads to their eventual marriage. Shortly after his wife's younger self first meets him, he dictates to her a list of the dates on which he will reappear; when she eventually meets his present self (who has not yet traveled into the past to meet her), she gives him the same list of dates, which he memorizes so that he can dictate it to her when he travels into the past. Neither character can figure out how or where the list originated.
Taken from http://en.wikipedia.org/wiki/Ontological_paradox
Oh man!
