Mostly I play Camarilla Larp (White-wolf RPG products, like Werewolf, Mage, etc), which is based on a simple card draw +stat system.
An example of Larping in motion.
At a convention once, I was walking around as my Malkavian in order to help a pair of friends who were Storytelling, essentially being a NPC.
So as I'm walking, I see this blowhard of a Bruhah yapping away and being ignored by everyone who can afford to. He's big, bad, and has an ego about his character, and I consider doing something about it until all of a sudden I see one guy starting to do the macarana. I'm wondering what's up, until a friend of mine taps me on the shoulder and says "Hey, you know the Story teller? Can you keep time?"
I realize immediately what's going on, draw a card (quickly) for an occult lore roll, ace it, and tell the GM that I am as far away and behind as many walls as my malkavian legs can take me. Others hear this, and quickly assume something must be wrong if the malkavian took off in a panic and did so in a fashion that he had to tell the GM about it. Another player's eyes go wide, as he realizes what is going on, and reaches record speed with celerity, the same as I did. A mass exodus ensued. Of course, no one warned the Brujah.
The Brujah is still going to town, now yelling at the dancer, as I wonder if he'll figure it out in the next minute that either (a) most of us were gone and (b) that wasn't a vampire he was talking to. The dancer by this point is twirling around. At last, the brujah says, "if you don't stop right now, I was kill you where you stand."
His response? He catches one last glimpse at his stop watch, and the Corax drops to his knees, finishing the ancient ritual by calling out "Helios, him me with some loving!", beaming the essense of the sun from his very core while the Werewolf I came with laughs hysterically.
Since it was deemed that the rest of us had ran so far away as to be out of play for the next hour (as per the bird's plan), we celebrated it all in the hotel's pub.
Ah... Good times, good times.
