Ok the following can only be remotely understood if there is knowledge of what a Lucid Dream is:
Basically it is a dream where you realize youre dreaming and realize all is created by your mind so you can will the experiences you want as long as it lasts.
I think the next great technological advancement will be the unification of the mind and computers.
Eventually there will be a way to induce experiences and store and reproduce human perception onto a computer.
They are already experimenting it with blind people to introduce visibility. Once they have the visual and auditory cortex mapped suficciently it will be living in augmented reality.
Once that is done all that will remain is to map the specific neurological pathways that each individual person triggers when a perceived visual, auditory, or other sensory stimulus is perceived.
This will allow for the mapping of the release peptides and chemicals each person produces, in order to have a blueprint of a persons sensory perceptions and emotional responses of that person up to the date the last neurological pathway configuration was last mapped.
This means that a persons sensory personality can be copied onto a hard drive.
This also means that information from the hard drive can be programmed until the neurological configuration rearranges itself until it is a match. (also called brainwashing)
But only the Visual/and Auditory/kinetic information is necessary to create a Awesome Virtual Lucid dream experience that is shared.

So you could in those circumstances create the neurological pathways necessary to be able to lucid dream adeptly. either reconfigure your own neurological network or simply hook up to a computer which sends visual, auditory and kinetic information to the brain, Now the parts of the brain which actually control physical kinetic movement have to be shut down , which occurs naturally in a sleep state or trance , or else you might find yourself having some muscle spasms and possibly sleep walking type experiences.
So this would work best in a lucid dream experience while physically sleeping or in trance.

OK So lets say I want to have a lucid dream with a friend and have it be themed Star Wars Style.
a simple way would be to have a commercially produced Neurological dream configuration of the minds behind those movies ( I'm guessing LucasArts of the future might release something like that). The Dream Space-Time would be created as a programmed finitely timed reality or it could be creating itself constantly if each player is given creative rights to be imported into the reality.
Lucid Dreamers are able to create at will anything they wish, But in a shared Lucid dream environment that exist on a computer virtual dream world only those with certain creative privileges are accepted by the environment's engine to be accepted as its space time custom rearrangement by the lucid dreamer(s) or else the dream world would cease to be shared because everyone will be creating and destroying according to their own desires, and others will not accept that dream and wake up.

This could be only temporary and custom for individuals or private dream groups and be set to default to most lucid dreamers in that shared lucid environment.
Rules can be programmed to ensure that the shared lucid dream is mantained at certain levels of lucidity or above certain emotional frequencies so that the moment it begins to turn into a nightmare for either of the lucid dreamers , it will intervene and either send a message to 1 or all of the lucid dream group , abort the dream for the person with bad experience, or create a NPC or situation to get the group to follow the rules they set before falling asleep.
Also dream check points would have to be created each time a person falls out of the REM cycle, to allow them to return at a later time to the dream.

There are many other aspects to this idea I am leaving out , but I do believe that this will be a possibility and the best way to experience a Game,Movie, experience with others. The best graphics, best sound , best storylines, best relationships.
Because it will be us experiencing a world with only the limitations we programmed the session for and being able to connect to the perceptions of other minds.

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We are the gamers constantly programming our experience