Thru the mirror

While watching another episode of "Charmed", I believe the last episode of season 5.  I came upon another interesting adventure idea.  Seriously you need to re-watch that show on netflix!   Anyways, the gist is that there is a parrellel world where everything that is good is evil and everything that is evil is good.  So the charmed ones are evil, the demons are good.  Demon of fear, is now the demon of hope.  Within the episode there is a crossover thru a mirror, where the characters are able to talk to there counterparts.  Now here is where it could be interesting in a role playing situation.   Let's say we create a dungeon, not a huge one, like 8 rooms or so.  After that create a mirror image of all the rooms.  The PC's get to a room where there is a mirror and they can see themselves in it.  All of a sudden out of nowhere they switch places with there other selves.  Cue CHANGE OF ALIGNMENT! 

Where this could be cool, is if for whatever reason you have a NPC that is chaotic but is trying their best to not show it, all of sudden they become good, and I mean really good like sparkles and fairies and rainbows good.  And now your Cleric or Paladin rather than being virtuous, are the embodiment of evil.  Obviously this premise would take some doing/planning on the part of GM.  Orcs are good, fairies are evil, dragons are good, elfs & halfing's are evil.

Within the episode the 2 sides had to work together for the common good of both worlds, as the balance of good & evil was extremely upset by having the counter parts in the wrong worlds.

Its a interesting premise, one that I may take further.