I've encountered some broken .deb packages in Humble Indie Bundle 3 like Osmos and Revenge Of The Titans. To install Osmos, from the command line:
$sudo dpkg -i [deb package]
Warning: This method may generate broken packages. To fix this, run Ubuntu Software Center and a pop-up will appear telling you to repair the broken packages. Click repair. It will download the missing packages.
Or, you may try to install the .tar.gz files rather than the .deb packages (Haven't tried this but it may work, and which is safer).