It works for me on Mac.

~$ curl -O http://code.angularjs.org/1.0.1/angular-1.0.1.tgz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 2946k  100 2946k    0     0   440k      0  0:00:06  0:00:06 --:--:--  476k
~$ md5 angular-1.0.1.tgz 
MD5 (angular-1.0.1.tgz) = a2be8ef9a31c5269c21e79c776bbdd3f
~$ tar -xvzf angular-1.0.1.tgz 
x ./
x ./angular-1.0.1/
...
...
...

I'm going to close this unless you can repro the issue. Also please check the md5 hash to verify that your file is not corrupted.

Same thing happened to me on Ubuntu. gunzip then tar worked though.

the problem is that the file is compressed twice:
$ ls -l Download/angular-1.0.1.tgz
-rw-rw-r-- 1 me me 3016474 2012-08-13 18:20 Download/angular-1.0.1.tgz

$ file Download/angular-1.0.1.tgz
Download/angular-1.0.1.tgz: gzip compressed data, from Unix

$ tar tzvf Download/angular-1.0.1.tgz
tar: This does not look like a tar archive

$ gunzip -v Download/angular-1.0.1.tgz
Download/angular-1.0.1.tgz: 0.0% -- replaced with Download/angular-1.0.1.tar
$ ls -l Download/angular-1.0.1.tar
-rw-rw-r-- 1 me me 3017355 2012-08-13 18:20 Download/angular-1.0.1.tar

$ file Download/angular-1.0.1.tar
Download/angular-1.0.1.tar: gzip compressed data, from Unix, last modified: Mon Jun 25 23:19:55 2
012

$ tar tvf Download/angular-1.0.1.tar
works... (aparently tar tries to decompress even without the z option)
$ tar tzvf Download/angular-1.0.1.tar
also works...

$ mv Download/angular-1.0.1.tar Download/angular-1.0.1.tgz
$ gunzip -v Download/angular-1.0.1.tgz
Download/angular-1.0.1.tgz: 50.0% -- replaced with Download/angular-1.0.1.tar

$ ls -l Download/angular-1.0.1.tar
-rw-rw-r-- 1 me me 6031360 2012-08-13 18:20 Download/angular-1.0.1.tar

$ file Download/angular-1.0.1.tar
Download/angular-1.0.1.tar: POSIX tar archive

$ tar tzvf Download/angular-1.0.1.tar
gzip: stdin: not in gzip format (as expected, it's no longer compressed)

@eMBee the file is definitely not compressed twice.

We use the following command in our Rakefile to create it:

  %x(tar -czf #{path_to(tarball)} -C #{path_to('pkg')} .)

I think that there is some kind of incompatibility between the mac and linux version of tar, which while weird, is plausible.

$ tar --version
bsdtar 2.8.3 - libarchive 2.8.3

we can try using gnutar:

$ gnutar --version
tar (GNU tar) 1.17
Copyright (C) 2007 Free Software Foundation, Inc.

and see if that makes a difference, or just use zip and get the windows-friendly benefit in addition to fixing the linux issues.

please take a look at the filesize when it is uncompressed the first time.
it only changes a little. and then check the resulting filetype.

i can't imagine how an incompatibility causes gnutar to have to decompress twice.
perhaps the resulting tarfile is compressed again when it's prepared for upload and the checksum is being created.

i can't find a script that calls 'rake package' though, so maybe that's done manually

we definitely don't compress twice. I don't know what's the problem, so I'm just going to switch to zip

@IgorMinar Just noticed the readme needs to be updated, too.