6. Verne Troyer
Being one of the shortest men in the world hasnt done much to hinder Verne Troyer, who despite having experienced a number of scandals in his life, has appeared in a number of films and television shows, most notably the Austin Powers series in which he played Mini-Me, a tiny clone of the villainous Dr. Evil. He also has the distinction of being the only American actor (to my knowledge) to have a speaking part in the Harry Potter series. In the first film, the Philosophers Stone, he plays the role of Griphook the goblin under heavy makeup, escorting Harry and Hagrid to Harrys vault in Gringotts bank. The character returned in the final two films, but Troyer was not asked to return, the role instead being played by Warwick Davis, who also played Hogwarts Professor Filius Flitwick throughout the series.
5. Michelle Fairley
Before she became Catelyn, the matriarch of the Stark family, on Game of Thrones, Michelle Fairley was merely an occasional stage and television actress who managed to secure the small role of Mrs. Granger, Hermiones mother, in part one of Deathly Hallows. Despite extensively featuring Rons family, neither the books nor the series offered much insight into the lives of Hermiones muggle parents. After their daughter alters their minds and has them move to Australia to protect them from possible harm at the hands of Voldemort, they are never mentioned again. On a related Game Of Thrones note, the role of a fifteen year old Voldemort in the Half Blood Prince was played by Frank Dillane, the son of Stephen, who plays Stannis Baratheon on the HBO show.