I just downloaded raspbian from raspberrypi.org/downloads, and I cannot unzip the archive. (I am using ubuntu 12.04)
Archive Manager says:
7-Zip  9.20 Copyright (c) 1999-2010 Igor Pavlov 2010-11-18 p7zip Version 9.20 (locale=en_US.UTF-8,Utf16=on,HugeFiles=on,2 CPUs) Error: /home/homie/Downloads/NOOBS_v1_3.zip: Can not open file as archive Errors: 1
and unzip complains that
Archive: Downloads/2013-09-25-wheezy-raspbian.zip End-of-central-directory signature not found. Either this file is not a zipfile, or it constitutes one disk of a multi-part archive. In the latter case the central directory and zipfile comment will be found on the last disk(s) of this archive. unzip: cannot find zipfile directory in one of Downloads/2013-09-25-wheezy- raspbian.zip or Downloads/2013-09-25-wheezy-raspbian.zip.zip, and cannot find Downloads/2013-09-25-wheezy-raspbian.zip.ZIP, period.
I've tried the same with NOOBS_v1_3.zip, with the same result.
Edit: I checked the shasums, and they don't match. So apparently the files are corrupted.