Last weekend's Jon Stewart/Stephen Colbert rally in Washington drew quite a crowd -- in the estimates of Stephen Colbert, 'over six billion people.' More reality-based estimates were somewhat less. Crowd-counting is a difficult task to take on, with event organizers obviously hoping to put the largest possible spin on the numbers. We'll talk about techniques used to get more accurate estimates of crowd sizes. Can you think of a better way to count? Can crowdsourcing help? Post your suggestions below.
Produced by Annette Heist, Senior Producer