I'm currently the DM for a group playing a 4th Edition Dungeons and Dragons campaign in the Neverwinter Campaign Setting.
In a recent adventure, my players asked me some unexpected questions, I said "yes, and..." a few times, and they've ended up in a tower randomly teleporting between planes. This was not at all planned.
In fact, they have places to be. They were in the middle of some time sensitive events, and should really be getting back. I don't want them to fail this objective, as it's kind of central to the whole campaign so far. That being said, I'd also like to do this little side adventure justice, as it could be a pretty fun way to confront the party with some stuff they wouldn't see in the place where the normal campaign takes place.
To this end, I was wondering if there was any precedent, in the Forgotten Realms or Dungeons and Dragons in general, for time distortion when traveling between planes. By this, I mean that when the party gets back to where they started, more time will have passed for them than has passed at the origin. This would be similar to science fiction stories where someone travels near light-speed for a long period of time, or the Chronicles of Narnia when they come back out of the wardrobe.
This travel was near the end of the session, and I was careful not to paint myself into a corner. The two places they've visited were only for about 30 seconds each, they haven't left the tower, and they didn't have time to identify the places with certainty. I can decide where they're going next, as the tower is teleporting randomly, and can retcon where they've been, since they don't really know.