// Sets the rigidbody velocity to 10 and in a random direction.

rigidbody.velocity = Random.onUnitSphere * 10;

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void Example() {
        rigidbody.velocity = Random.onUnitSphere * 10;
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def Example():
        rigidbody.velocity = (Random.onUnitSphere * 10)