My LARP System

This is the house system I use when I run live action roleplaying games, newly revised for a game I'm planning on running in the spring.

Tests
At the start of the game players get two playing cards, one black and on red. During a test both players chooses one of their cards to compare to the other player's card. When both cards are the same color, the active character succeeds, and when the card are different colors, the active character fails.

A player starts a test by declaring what their character intends to do. Tests are for actions that can't normally be roleplayed normally and tend to have a scope larger than a single action—beating someone up rather than throwing a single punch. Possible examples of declarations: "I'm going to slip a note in your pocket," "I'm going to use this power on you," "I'm going to make you bleed."

Test are generally between two players (though they might effect more characters). The one exception is the Hero Rule—when a firearm (or similar weapon) is being used in a test, a character can throw himself or herself in the way—all three players draw a card if the cards match, the active character is still successful, but if even one card doesn't match, the third party take the hit.

A player can always opt to allow something to happen to their character without a test.

Injury
The is a limit to how much injury a character can take in a single test. After a single test designed to injure a character, that character is hurt. A second test (which can't be made during the same scene) against a hurt character can kill that character. Being hurt only lasts until the end of the episode.

Weapons can kill character without hurting them first.

Ownership
Locations in the game can be under the auspice of one of the players. The location is like part of that player's character, and someone trying to do something to that location—such as breaking into a building—should go to that player and ask for a test.

Plot Holes
Each character has one plot hole, which can be used to either heal a hurt character in the middle of an episode or to resurrect a dead character between episodes.

Traits
Characters have traits, which sometimes come into play during tests either by allowing you to make different types of tests, or to retaliate when someone fails after starting a certain type of test against your character.

Many traits have a limited number of uses which are refreshed at the end of the episode.