I didn't know the name of the cactus aliens, I didn't know the pre-title drawing was from The Doctor, The Widow and the Wardrobe (I didn't think it was very good so I only watched it once and don't remember how it began), I didn't know what the Doctor wished Santa Claus since I only got about 5 minutes into Last Christmas (I only got question 15 right, which was also about Last Christmas, by guessing), and I forgot about Clara leaping on top of the carriage.