how to access a scripts parent or calling object

Questions & Answers
1

how can I access the scripts parent game object to get access to other scripts attached to the parents?

2 
transform.parent.gameObject

Will give you the parent of the current game object.

5

Actually, if you are wanting the object the script is attached to you can just use gameObject directly.

Debug.Log("I'm attached to " + gameObject.name);

And for sibling scripts (Other scripts attached to the same GameObject) you can use GetComponent straight up.

C#

otherScript MySibling = GetComponent<otherScript>();
3

To get the scripts of the parent game object, just do the following based on what SpikeX said:

transform.parent.gameObject.GetComponent<ScriptName>(); // C# version

transform.parent.gameObject.GetComponent(ScriptName);   // JavaScript version

More information can be found here: Link

4

to access the gamobject that is calling the current script do:

var obj : GameObject;
obj = gameObject;

it would be the same as doing transform.parent.currentScript instead of transform.parent.gameObject if currentScript actually existed.