My church includes some lessons in playing RPGs in it's Sunday school teacher training - and to the children in the program.
At the First Unitarian Church of Portland Oregon, a program called Creative Combustion is used to train the religious education (Sunday school) teachers. The program is also used with the children and youth to develop trust and group cohesion in the classes.
The program uses a variety of exercises to build trust and group cohesion.
One game, Fruit Basket Upset, which is a chair swapping game, has a rule that's interesting to consider for RPG play: There is no Fruit Basket Upset police. Basically, what this rule means is that if someone doesn't get up when they're supposed to, you don't call them on it (though raising an issue where perhaps the game is being misunderstood is a different ball of wax). That rule might not be appropriate to an RPG is it's most open sense, but the idea behind it is worth considering.
One of the significant concepts is Offers and Blocks. This concept is very relevant to RPG play. The idea is that when someone offers something to the group (significantly in RPG play, creative input), the idea is not to block by shooting the idea down, or not paying attention, or in any way dismissing the idea. That doesn't mean that you say yes when some kid says, "Hey, let's burn the church down!"
Connected with the Offers and Blocks are two games, that by Vincent's definition of an RPG (the players agreement creating a shared imagination space) are RPGs.
The one that when I look back on when it has worked really well is obviously an RPG is Two-Headed Adventure. In Two-Headed Adventure, players pair up. The game is played by the player alternately saying a single word (though often pairs wind up saying a very short phrase - but this can be a dangerous drift). As the players create their story, they are free to move around and gesture. An example might be:
"Look! (player points) - a - river! - Jump! (players jump) - Jello! - Strawberry! - I'm - starving! - Thank - goodness - we - found - food - before - the - giant - found - us!"
Notice how a story unfolds that exists only because the players accept and agree to each other's creative contribution.
Gift Giving is a similar game. One player offers a gift to another. The gift is unspecified. The second player pantomimes opening the gift and then starts describing it. The first player may respond by giving encouraging statements (such as "I knew you always wanted a new car" after the second player says "Wow, a Red Mustang with chrome wheels!").
I believe that these exercises come from improvisational theater training. They have been helpful to me in thinking about how to better empower players in my games.