I saw a post which said Ryan Gosling was in an episode of Goosebumps, but were there any other now-famous actors/actresses that appeared in this series?
shareColin Mochrie was in Bad Hare Day. I'm not sure how famous he is, but I know him from Whose Line Is It Anyways http://www.imdb.com/title/tt0163507/?ref_=nm_knf_i1
shareNot a Big Name but Harvey Atkin was in Bad Hare Day and Atkin played a judge on Law and Order SVU for like 11 eps
Charlotte Sullivan was in Bad Hare Day and she has been on the show Rookie Blue,played Maixma on Smallville and Marilyn Monroe in the min series the Kennedys
Barcaly Hope who played Col. Lionel Pendergast on Stargate SG-1 was the father in Piano Lesson can be Murder
sharenot a famous actor, but William Fruet (known for directing low budget horror/exploitation movies such as House By The Lake, Funeral Home, Spasms and Killer Party) directed 12 + episodes. got really excited when I watched the show as an adult and saw his name pop up in the credits.
shareAnais Granofsky - Lucy from Degrassi (Junior) High - played the teacher in "You Can't Scare Me!"
and Daniel Clark (Sean from Degrassi The Next Generation) in "How I Got my Shrunken Head"
Brooke Nevin, she was in the episode A shocker on Shock street. She has made guest starred appearences on Smallville, CSI, Supernatural, Gray's Anatomy, How I met your mother and many other shows and movies.
shareI also forgot Caterina Scorsone she was in the episode Night of the living dummy 2 and Chillogy part 1, 2 and 3. Caterina has starred in shows like Missing, Private practice and Grey's Anatomy.
shareJim Belushi played The Masked Mutant in the video game but (oddly enough) not in the Attack of the Mutant episode. I'd say Gosling is the only one to became hugely successful after the show. He didn't reprise his role in Say Cheese and Die Again though. Perhaps he was considered too old when they got around to doing the sequel episode.
Hayden Panettiere was not in Goosebumps but did have an early role in Malcolm in the Middle.