The question, "what time is it?" seems simple on its face, but it is a question that delegates to the World Radiocommunication Conference will struggle with when they meet in Geneva this November. At issue is whether to keep the world's definition of time as it is, or to alter it by removing the concept of a leap second.
On 26 occasions since 1972, clocks around the world have stopped for one second to adjust for the difference between the Earth's rotation and Coordinated Universal Time (UTC, under the French acronym). Those adjustments mean the sun remains over the Prime Meridian at noon, but they also cause a host of problems for computers worldwide. For example, the leap second that happened on June 30, 2012 crashed the software powering airline reservation systems in Australia, and also led to issues with services including Reddit, Foursquare, and Yelp.