Unity FPS Shooter Game tutorial #6

http://unity3d.com/support/documentation/ScriptReference/Component.BroadcastMessage.html

Component.BroadcastMessage  

function BroadcastMessage (methodName : string, parameter : object = null, options : SendMessageOptions =SendMessageOptions.RequireReceiver) : void

Description

Calls the method named methodName on every MonoBehaviour in this game object or any of its children.

The receiving method can choose to ignore parameter by having zero arguments. if options is set toSendMessageOptions.RequireReceiver an error is printed when the message is not picked up by any component.

/// Calls the function ApplyDamage with a value of 5
BroadcastMessage ("ApplyDamage", 5.0);

// Every script attached to the game object and all its children
// that has a ApplyDamage function will be called.
function ApplyDamage (damage : float) {
print (damage);
}