// Draw a yellow sphere in the scene view at the position
    // on the near plane of the selected camera that is
    // 100 pixels from lower-left.
    function OnDrawGizmosSelected () {
        var p : Vector3 = camera.ScreenToWorldPoint (Vector3 (100,100,camera.nearClipPlane));
        Gizmos.color = Color.yellow;
        Gizmos.DrawSphere (p, 0.1);
    }

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void OnDrawGizmosSelected() {
        Vector3 p = camera.ScreenToWorldPoint(new Vector3(100, 100, camera.nearClipPlane));
        Gizmos.color = Color.yellow;
        Gizmos.DrawSphere(p, 0.1F);
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def OnDrawGizmosSelected():
        p as Vector3 = camera.ScreenToWorldPoint(Vector3(100, 100, camera.nearClipPlane))
        Gizmos.color = Color.yellow
        Gizmos.DrawSphere(p, 0.1F)