Installing R offline in Ubuntu

Hi,

I've just bought a new laptop, which will have Ubuntu Linux
pre-installed.

When it arrives, one of the first things I want to do is to install R.
However, when I went to look at the instructions on the CRAN site, it
seems that they are geared towards computers that are connected to the
internet.  Mine won't be: I've always reserved my home laptop for
working offline.

So my question is:  Are there any instructions for installing R on an
offline Ubuntu machine?  (This process was pretty straightforward with
the MS Windows distribution of R: you just downloaded the .exe setup
program and ran it...)

Many thanks,

Andrew Wilson