A game for 8+ players and a GM.
The GM makes a series of cards, which describe who you are AND the situation you’re in. He makes one for all players minus two.
One card simply reads “You’re the Doctor”
He also makes a card for each player that reads “You’re the villain”. If the GM prefers, he can pick a pre-existing villain, or come up with his own. One of these cards is shuffled into the deck, so that there is one card for each player.
Each player is then dealt a card face down, and does not reveal what it says. Then everyone closes their eyes and the villain raises their hand. The GM gives him the rest of the “I’m the Villain” cards.
The other cards give you an idea of who you are, which might be specific (“A catperson space hitchhiker”, “Napoleon”) or general (“one of the elite mining crew”, “one of the rebel street gang”). There should also be a scenario with a problem to be solved. It might be something like “Ancient Egypt has collided with rogue Silurians and Snake Cults threaten to destroy the Fifteenth Dynasty” or “The first woman on Mars is dead and nobody knows who killed her because she was alone out there – or was she?”. Each card might have slightly different information on it, if your GM is feeling malicious.
The GM sets the scene slightly, giving a few hints about perhaps where everyone is or what they can see. Then everyone has thirty seconds to roleplay. Importantly, the Doctor and the Villain have no idea what is going on. However, the rules of Theatresports are in play which is to say: anything anyone declares to be true is true. Because the people in the scenario know what they’re talking about, and because the Doctor is always right, and because the Villain planned it that way.
After one minute, each player MAY show their card to one other person. Based on the roleplaying, they may have an idea who is the Doctor or the Villain. If someone shows you their card, you show them yours.
If you see a card with a scenario on it, you learn who the person is playing so you can sound more authoritative in the next round.
If you see a card that says “I’m the Doctor”, you know who the Doctor is. From now on, your hopes are higher. Do what he says, he can save you! Agree with what he says because he’s right!
If you see a card that says “I’m the Villain”, you are now one of the villains minions, either willingly or unwillingly (or perhaps even unknowingly). Do everything he says. Agree with what he says. Also take a Villain card from the Villain – and in subsequent rounds, that is what you show people, not your original card.
If the Doctor sees a card that says “I’m the Villain” the game is over, and you move to the finale stage. If the Doctor doesn’t see such a card, repeat the round as above: thirty seconds of roleplaying, then a show of cards. The GM may introduce another fact to the scene, or change things slightly (“Another crew member has been killed!”, “you’ve reached the bridge”). Keep going through rounds until the Doctor encounters a Villain. When he does, he should shout “OF COURSE!” or something similar. Then he should introduce himself.
When the finale is triggered, all Villains raise their hands. Count up how many people are villains. Then everyone who is not a Villain raises their hand if they have met the Doctor. If there are more in the first group, the Villains have won! The Doctor is then forced to explain that he arrived too late, and a lot of people are going to die but maybe, just maybe, he save the universe at great personal cost.
If there are more in the second group (non Villains who have met the Doctor), the Doctor has solved the problem in time. A tie goes to the Doctor’s side. There may be some loss, but he can redeem them somehow – cure the infected, counsel the evil. The Doctor and his allies explains how he solved things, with the help of timey-wimey effects and a sonic screwdriver.
Then the GM should hand out some new cards and play again. This time, there’ll be a new Doctor and a new Villain to unmask!
Remember that both the Doctor and the Villain want to be found, but not too quickly. Spread your guesses around, and act clueless to help protect the Doctor at the start. This will of course also protect the Villain….