I am trying to download and/or acquire an operating system installer for my newly purchased Mac. My objective is to put this onto some form of removable media (USB ideally) such that in the event that my tinkering renders the Mac unusable, I can fix it.
My initial understanding was that I needed to purchase OS X from the app store. I am trying to purchase OS X 10.8.2. I am running 10.8.2. Yet the app store responds with "sorry, this is not compatible with your Mac" !!

So that's out. So, question time:
- Is this the right way to achieve what I want, bearing in mind I explicitly want removable media with a full installer?
- If so, how do I convince the app store that it is being silly?
- I hear rumblings that the installer can be fished out of the recovery partition? Be this true? If so, where on this volume is it (I can mount it, and I looked around, but I don't see anything that looks like an installer).
