trajectory lobbing script

is there a simple (or complicated) script that describes the trajectory of an object, for instance, the lobbing of a grenade?

The simplest way to do this would probably be using the physics engine. Attach a rigidbody to your grenade object (or prefab) and set it to use gravity (there’s a checkbox in the inspector). Then when you want to throw a grenade, just do something like this (untested code, may need some adjustment):

var grenadePrefab : GameObject; 

var grenadier : GameObject; //This is whatever is throwing the grenade, i.e. the player, enemy character, etc.

var elevationAngle : Vector3 = new Vector3(45,0,0);

var throwForce : float;

//Creates a new grenade and throws it with the set force and elevation.
function ThrowGrenade()
{
	var grenade : GameObject = Instantiate(grenadePrefab, grenadier.transform.position, Quaternion.identity);

	var elevation : Vector3 = Quaternion.Euler(elevationAngle) * grenadier.transform.forward;
	
	newGrenade.rigidbody.AddForce(elevation * throwForce);
}