The Parallax colony
Parallax Colony mud baths
The Parallax colony was a colony of "free spirits" on the planet Shiralea VI, populated by fanciful humanoids concerned only with a life of pleasure. Included in this society was the Juggler, an argumentative couple, a poet, and a wind dancer. "Only those whose hearts are joyous" were permitted to enter.
Lwaxana Troi introduced Alexander Rozhenko to a holodeck simulation of the colony in 2368, to enjoy the "laughing hour" and the colony's famous mud baths. Alexander enjoyed them, but Worf failed to understand the point of just "sitting here" in the mud. (TNG: "Cost Of Living")