Gaurav Tekriwal, President of the Vedic Maths Forum in India, is an educator who teaches the joys of ancient mathematic techniques.
Daniel Tammet has linguistic, numerical and visual synesthesia, meaning that his perception of words, numbers and colors are woven together into a new way of perceiving and understanding the world.
Margot Gerritsen, PhD, is an Associate Professor of Energy Resources Engineering, with expertise in mathematical and computational modeling of energy and fluid flow processes. She teaches courses in energy and the environment, computational mathematics and computing at Stanford University.
Newton Leibniz and Usain Bolt: Why we study differential calculus.
(from the great KhanAcademy.com)
Tracking a tennis game - a 17-state Markov Chain
TED talk on the awesome, wierd, wonderful world of Fibonacci numbers (more info on Wikipedia: Fibonacci).