Egyptians use their mobile phones to record celebrations in Cairo's Tahrir Square, the epicenter of the popular revolt that drove Hosni Mubarak from power in 2011. Twitter was often used to record happenings during the Arab Spring. Mohammed Abed/AFP/Getty Images hide caption

itoggle caption Mohammed Abed/AFP/Getty Images

Festival attendees experiment with Leap Motion technology. Elise Hu/NPR hide caption

itoggle caption Elise Hu/NPR