(The Paris Observatory, in France has said that 30 June 2015 will be one second longer, as what is called a "leap second" is added to the day to account for discrepancies between Earth time and atomic time, due to the slowing rotation of the Earth.
This will be the 26th leap second to be added since 1972, and the extra second will be added at 11:59:60pm UTC on 30 June, bringing the total number of seconds for 2015 up to 31,536,001.
What will you do with your extra second?)