How to rotate object when thrown?

Okay so I have project where I have a molotov being thrown and I want it to rotate as it does in video games. Can someone please help me please?

This is all I have so far.

var projectile : Rigidbody;
var speed =30;
var rotation = 1.0;

function Update()
{
	if( Input.GetButtonDown("Fire1"))
	{
		rotation += 0.2;
		transform.Rotate (rotation,0,0*Time.deltaTime);		

		var instantiatedProjectile: Rigidbody = Instantiate( projectile, transform.position, transform.rotation);

		instantiatedProjectile.velocity = transform.TransformDirection( Vector3(0, 0, speed));
		Physics.IgnoreCollision( instantiatedProjectile. collider, transform.root.collider );
	}
}

I , too, have a rotating thrown bottle but I did it differently. I instantiate the bottle at the release point of my hand with addForce to get the distance, but the rotation itself is a looping animation of the bottle prefab spinning set to play automatically. So I throw, it spins, then blows up. I don’t get the satisfaction of saying I did this by typing words in a script, but I do get the satisfaction of seeing my bottle spinning with a flame on it and exploding upon impact and setting bad guys on fire and they run around screaming like little school girls

http://unity3d.com/support/documentation/ScriptReference/Rigidbody.AddTorque.html