http://originallonemagpie.tumblr.com/post/98823492812/october-31-days-of-halloween

Day 28 - Favourite horror-themed or spooky game.

Notice it doesn't say "videogame" (that answer would be Eternal Darkness: Sanity's Requiem). The overall answer, of course, is Chaosium's pen and paper RPG, Call Of Cthulhu.