// Set the text of the attached Text mesh
var newFont : Font;
GetComponent(TextMesh).font = newFont;

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
public Font newFont;
void Awake() {
GetComponent<TextMesh>().font = newFont;
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

public newFont as Font

def Awake():
GetComponent[of TextMesh]().font = newFont