Download Zip File

I have tried to use rio gem to download a zip file (in windows) but it results in a corrupt d/l. I think this is because binary mode is not available in rio.
So I am now trying to use open-uri

require 'open-uri'
f = open (url)

f is of class tempfile. How do I save this temp file to disk?
Does open-uri have a binary mode option, or is it the default?

Or is there a more elegant ruby way to d/l binary mode files ?

Thanks
Paul Fraser

I used the example at http://snippets.dzone.com/posts/show/2469 to
download some pictures, the "wb" is important, so that the file is
opened in binary mode, otherwise you'll end up with ascii mode and
your file contains corrupted data.