In which we explain economic equilibrium, how to make money from nothing, and every fundamental force in physics. If you'd like to read a (very) rigorous description of gauge theory in economics, check out this paper by Lee Smolin: http://arxiv.org/pdf/0902.4274v1.pdf And if you're an economist rather than a physicist, check out "The Index Number Problem: A Differential Geometric Approach" by Pia Malaney: http://bit.ly/JKS5lh minutephysics is now on Google+ - http://bit.ly/qzEwc6 And facebook - http://facebook.com/minutephysics And twitter - @minutephysics Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Music by Nathaniel Schroeder Thanks to Nima Doroud for contributions and to Perimeter Institute for support. http://www.perimeterinstitute.ca