The recreation room was an area of a starship where crewmembers could go to enjoy games and other activities when off duty.
Constitution-class starships such as the USS Enterprise had at least six recreation rooms. One such area, recreation rooms 6, was located on deck three. (TOS: "Charlie X") Another, recreation room 3, was located on deck five, near the crewmen's lounge. (TOS: "Let That Be Your Last Battlefield")
At least one of these recreation rooms was capable of holographic projection, serving as an early holodeck. The Enterprise was outfitted with such a room in Area 39 of the ship as early as 2270. This rec room was capable of creating pre-programmed illusions using with holographic scenes, simulated weather including wind and temperature, and sounds played from audio tapes. Some scenes it created included an 18th century European hedge maze, forests, blizzards, and a beach with seagulls. (TAS: "The Practical Joker") These types of rooms aboard starships were likely phased out before the turn of the century, as Harry Kim claimed that starships of that era were not equipped with holodecks. (VOY: "Flashback.")
