The Net is a recreational facility on Deep Space 15 that was set up following Starfleet's departure in 2388 by the Selubassari.
Patrons are leased a neural experience node, placed on the back of the skull. During a session, the patron can experience just about anything he or she imagines, from a homeworld to a memory.
Controversy
The Selubassari claim that the experience is harmless, despite rare reports from humanoids of impaired brain activity afterwards.