IPython Notebook lets you interact with the python interpreter from your browser. It saves your work as a "notebook" file, which you can pass on to others, and which can be re-run.
IPython Notebook includes integration with MatPlotLib so that if you create any MatPlotLib graphs, they will automatically be displayed in your browser.
MatPlotLib makes the graphing capabilities of the powerful commercial MatLab tool available in Python. It, and all of SciPy, is built on NumPy.
NumPy gives blazingly fast, flexible, and memory efficient multi-dimensional numeric arrays to Python. It rightly claims to be "the fundamental package for scientific computing with Python".
Juan and Chris will lead a Teach Me session on these tools, where those in the audience familiar with these tools (and/or quick at google searches) will teach them how to use these tools.