I find the concept of the leap second quite interesting. It's a small adjustment, similar to the extra day in a leap year, used to adjust the time, as calculated by watching the sun rise, so it matches the time, calculated using an atomic measure.
Apparently, there's a discussion underway about abolishing the leap second entirely. The US (amongst others) want this done because every time there's a leap second they have to adjust the clocks on all their radio masts and the like. (Presumably, the assumption is that they're exactly and entirely accurate otherwise... perhaps someone should have spoken to an engineer before bringing that one up.)
Honestly, it really doesn't matter all that much. A second here or there? Who cares? Apparently, in about 550 years, the drift between the two will be about an hour, but that's far enough away that we'll have moved to the stars by then anyway. Or, more likely, wiped ourselves out. Either way, only the atomic time will matter.
The next leap second is scheduled to occur on the 30th of June.
Clearly, this must be stopped! The government are trying to steal part of my birthday!