PyLab_Works is a free and open source replacement for LabView + MatLab, written in pure Python. PyLab_Works is a visual design package, much easier to learn and to extend than LabView. PyLab_Works also supports a MatLab-like environment for doing scientific and engineering calculations but with a much better general programming environment (thanks to Python + Scipy) than MatLab. Even kids can use it!
It’s available at http://www.ohloh.net/p/pylab-works. Here’s a video about it
The part I like the best is where they use Python to simulate a pendulum. You can play with the parameters of the pendulum in the code. You can even change the way gravity works!