"Yes, and..."
I've been playing "Yes, And" with my kids. It's quite fun, and it's good practice for lots of important skills: taking turns, listening and responding (a.k.a. conversation), creative word-play, and of course how to be constructively rather than destructively cooperative.
For those who don't know what "Yes, And" is, it's a simple game often used in improv troops for practice of... well, all the skills I listed above. The rules are simple: each person takes a turn and describes something, generally an event, in one sentence. The next person (and every person after them) says another event, but must start the sentence with "Yes, and..."
But they must do this both syntactically and semantically. You can't say, "Yes, and that thing you said didn't really happen." Nor can you say, "Meanwhile, back at the ranch..." Each sentence must be a natural result of the one before it without nullifying the intention of it.
An example in case this isn't clear:
1. There was a robbery at the convenience store on the corner.
2. Yes, and the robbers were disguised as former presidents.
3. Yes, and they only took the beef jerky.
4. Yes, and the cops were able to follow them because one of the bags broke.
5. Yes, and the cops chased them to a construction site.
6. Yes, and the robbers didn't have guns, so they tried to chase away the cops by throwing bricks and rocks.
A few examples of what you could not do might be appropriate now:
7. Yes, and the robbers weren't really disguised--they were really all former presidents!
(We already said they were disguised--an alternate would be that they were all former presidents disguised as former presidents--but refuting the disguised part is a no-no.)
7. Yes, and what the cops thought were bricks were really guns.
(In this one, they are acknowledging the previous statement, but then altering it. Still a no-no.)
7. Yes, and then the robbers stopped throwing rocks and agreed to give all the beef jerky back.
(This is almost OK, but it's denying the spirit of the statement before--why did the robbers abruptly decide to stop throwing things?)
7. The Tarzan the Apeman came swinging into the construction site, grabbed the beef jerky, and took it back to Africa for his friends the lions.
(This is ok in some games, but you're totally breaking the context by injecting a new genre. So it's arguable that this is breaking all the expectations people had put in place for the world the characters were operating in. But in other games--like the ones you're going to play with a 5 and 3 year old--this is totally fine.)
7. Then the robbers threw rocks and the policemen shot their guns until all the robbers were dead and the cops took all the beef jerky but said they didn't take it so they had all the beef jerky to themselves back at the station while they laughed and laughed at the robbers and the store owners.
(This is really more than one event.)
So that's "Yes, And." Once you get the idea it's easy to play, though there is a bit of a learning curve. But anyone can play it so long as they can construct a narrative. I'd say vocabulary is a more likely bottleneck than narrative construction in terms of maturity limits.
But here's the thing I just connected up. I think ideally role-playing games should be a game of "Yes, And." Normally you'd consider that and say, "But people can fail at tasks." Ah, but what if you considered the process this way:
Player 1: Tyrone the thief tries to pick the lock on the door.
GM: Yes, and while he does that he trips a tiny wire and everyone can suddenly hear a ticking noise.
Player 2: Yes, and when Bertrand hears the ticking noise he peers around to see where it's coming from.
GM: Yes, and Bertrand can tell the sound is coming from the wall nearby but doesn't see any obvious openings.
Player 1: Yes, and Tyrone quickly backs away from the wall.
GM: Yes, and Tyrone and Bertrand are thrown backward by an explosion and take 2d8 damage.
So in my example here all the PCs failed every roll. But what if the GM acknowledged that everything the players said was irrefutable fact--and the players acknowledged that everything the GM said was fact. So instead of saying, "No, that didn't happen," you say, "Yes, that happened. And then this also happened."
But to do this you need everyone to remain aware of their limits. If Player 1 had said, "Tyrone the thief picks the lock on the door and it opens" then that's too much control. Likewise, the GM couldn't say, "You hear a ticking sound and the wall explodes and you take 2d8 damage." The players need to be able to react.
I think "Yes, And" is an interesting idea for a way to do role-playing because it changes how everyone interacts. Everyone does what they say, but sometimes they also have complications that come from what they did. You can also eliminate, "No, but before that happened I..." Make the gameplay in simple event steps. Something happens, then people have a chance to react.
I think it would show more respect, and it would make the dice and the GM the arbiter of complications and efficiency rather than success and failure.