Helper methods used within Unity3d

UnityExtensionMethods.cs

using UnityEngine;

public static class UnityExtensionMethods
{
    #region go_utils
    public static void Activate(this GameObject go)
    {
        go.SetActive(true);
    }

    public static void Dectivate(this GameObject go)
    {
        go.SetActive(false);
    }

    public static void ActivateGO(this MonoBehaviour mb)
    {
        mb.gameObject.SetActive(true);
    }

    public static void DectivateGO(this MonoBehaviour mb)
    {
        mb.gameObject.SetActive(false);
    }
    #endregion

    #region children_manipulation
    public static void DestroyAllChildren(this GameObject parent)
    {
        foreach (Transform childTransform in parent.transform)
        {
            Object.Destroy(childTransform.gameObject);
        }
    }

    public static void ActivateAllChildren(this GameObject go, bool activate)
    {
        SetAllChildrenActive(go, activate);
    }

    public static int GetActiveChildCount(this Transform transform)
    {
        int activeChildCount = 0;
        int childCount = transform.childCount;
        for (int i = 0; i < childCount; i++)
        {
            if (transform.GetChild(i).gameObject.activeSelf) { activeChildCount++; }
        }

        return activeChildCount;
    }

    private static void SetAllChildrenActive(GameObject go, bool active)
    {
        int childCount = go.transform.childCount;
        for (int i = 0; i < childCount; i++)
        {
            go.transform.GetChild(i).gameObject.SetActive(active);
        }
    }
    #endregion

    #region cloning
    public static T Clone<T>(this T unityObj) where T : Object
    {
        return Object.Instantiate(unityObj) as T;
    }

    public static T Clone<T>(this T unityObj, Vector3 position, Quaternion rotation) where T : Object
    {
        return Object.Instantiate(unityObj, position, rotation) as T;
    }
    #endregion
}

simple and clean