If you want to run the programs posted here you will need to have Python 2.7.4 interpreter, and VPython 5.12 (a 3D scientific library). Actually these are the versions which I work with, if you have newer or older ones you can try to run the modules anyway but be aware it won't always work.
I recommend you to install the IDLE programming environment because is specific for python. IDLE is very clean and useful because you can write scripts and talk to the interpreter directly among others... You can download easily all this software using the Synaptic package manager (in Ubuntu).
example: type "python visual" for VPython.
VPython main web
Python official website