Parallelizing bzip2 (and tar)
You have a multicore CPU but when you start a bzip2 operation only one core is used?, what a waste of resources!.
There is a version of bzip2 created to be used in that circunstances and it makes use of all available cores. Its name is pbzip2 and can be downloaded from here http://compression.ca/pbzip2/.
There are prepackaged versions and you can install it in Ubuntu easily because it's included in the official repository.
The usage is analogous to the single core version so you won't have to learn new options.
Bzip2's closest relative is, of course, tar. Tar doesn't have native suport for pbzip2 but can be added easily with the following option:
You could even make a shell alias to speed thing up.
Enjoy and squeeze every drop of cpu cycles on your machine!