Recently I happened upon a discussion on Google+ regarding the introduction of facts by players. The example given involved an Indiana Jones character spontaneously identifying snakes. Does the referee determine the kind of snakes or does the player determine the kind of snakes?
Wilhelm Person suggested a skill check to get narration rights:
When you roll for knowledge skills. If you succeed you get to decide what the truth is.
If you fail the GM tells you what the truth is. Sometimes the GM lies.
Here’s what I wrote:
If you manage to foster the right atmosphere at the gaming table, it can be just a matter of using an ellipsis, a pause, a knowing look—and players will interject cool ideas by themselves. That’s how I try to have it work at my table. The obvious benefit to me is that we don’t need a skill. Another benefit is that it limits itself to situations where players actually have cool ideas. Otherwise—particularly if you’re not playing a story game—you might get a helpless shrug or an empty stare in response to a success on the knowledge skill check. Players are not always ready to spew forth the Apocalypse.
What seems to work best, in my game, is to combine it with a 1 in 6 chance. Most players will immediately suggest something very positive for them. I might make a doubtful face and say “OK, 1 in 6 chance that these cannibals fall for your ridiculous explanation. But what if it doesn’t work?” Usually the table is in brainstorming mode at that point and we all determine the rest before rolling the die. I find that accepting all suggestions at the table and have the dice decide works better than discussing it, looking for consensus—long talk disrupts flow, as far as I am concerned.