The Doll Room is where one challenge in Season 1 takes place; that challenge is the Doll Challenge.
Episode 7 - Mermaid Tails
Matt and Tim are chosen for the challenge and they go into a room and there is a doll house on each side of the room, as well as a ton of dolls around the room. A note on the table tell them that they have to take a drink to know more. There are two wine glasses with a red liquid inside and they each take a sip. A note comes from under the door that says they've been poisoned and they will get three nursery rhymes that they have to copy with a doll that fits the description, and once they find the correct doll they must place it inside of their dollhouse; according to how the rhyme tells them to. If they get the placements wrong, they will get more poison. If they get the placements right, they will get the antidote. They both finish at the same time, and a vial of liquid comes out of each of their drawers. Matt says that he is one hundred percent sure that he has won, and then takes a sip of the vial he received. The vial turns out to be poison, which kills him. Tim receives a note that informs him that neither of two had been given the antidote and that it was actually on the back of the drawer. After taking a sip of the real antidote, Tim receives the doll.