If you need to go into controlled airspace without permission


[CFI mode]
I fly in controlled airspace all the time and rarely get permission.
Controlled airspace does not mean that you have to talk to a controller.
Class E airspace is controlled airspace and is the such best example.
The only uncontrolled airspace (in the U.S.) is class G airspace.

Wikipedia, though never authoritative, provides this (accurate)
description - http://en.wikipedia.org/wiki/Controlled_airspace.

[/CFI mode]

Tony V. CFI-G