A common room was a shared lounge area in Hogwarts School of Witchcraft and Wizardry. There was one for each House. The common rooms featured fireplaces and sitting areas and were decorated in house colours. They were often used to do homework and to socialise with housemates. The boys' and girls' dormitories were also attached to the common rooms, with spells in place to prevent male students from entering the girls' dorms, but not vice versa, which Ronald Weasley felt was unfair. Learn More about Gryffindor