rec room
noun (North American English, informal)(also recreation room British and North American English)
a room in a school, a hospital, an office building, etc. in which people can relax, play games, etc. （学校、医院、办公楼等处的）娱乐室，活动室 - (North American English)
a room in a private house used for games, entertainment, etc. （私人住宅里的）康乐室