Portable Python can be installed on any USB storage device, local hard drive or network location. It is possible to install several different distributions of Portable Python on the same USB storage device (or local hard drive) and have them running side by side. This makes Portable Python ideal environment to test your code with different Python engines.
Open a terminal with Ctrl-Alt-T and execute the command below:
This will enable the feature in 12.04. Here is a screenshot from 12.04 Desktop: