A meteor falls from the sky, leaving no crater, only a freestanding, entirely normal-looking door. A unique but similar world lies on either side of... The Door. Separate players evenly-ish between two rooms (worlds) connected by The Door. Close The Door. Each group rolls a d8 to determine their society's rudimentary culture. 1- Benevolent 2- Peaceful 3- Apathetic 4- Cautious 5- Bold 6- Selfish 7- Aggressive 8- Other (players' choice) Each player looks around their side of The Door and explains how this culture contributed to one aspect of the room (windowless from caution, etc.). Each player rolls the die. This tells them the environment their character was raised in. They give a name, a brief description, and a reason why they have come to The Door (peaceful scientist, bold local politician, etc.). After all players in a world have done this, all players discuss in-character what to do with The Door. They may enter, talk through, look through, etc. with The Door. After going through The Door, ask about why things are different. Point to something rare in the other world and ask why it's in this one. That world's inhabitants should give an answer.
Based on a board game I’m working on. It’s amazing how much the game changes based on where its played. Even the door in question if it has windows or a lock or only opens one way. I know it doesn’t have an ending, but I wanted players to come up with their own goals.