On June 1 2010 Stephen Wolfram gave a talk on the International Conference on Computational Science in Amsterdam.
Wolfram is a true visionary of computational science. He has developed formula manipulator Mathematica and the computational knowledge engine Wolfram Alpha, and he has written the book A new kind of science.
During his talk Wolfram was using Mathematica and Wolfram Alpha for demonstrations. Obviously my audio recording does not show the images, but still listening to his talk is inspiring. Click here to listen to his talk.