There was a story on Slashdot ( http://science.slashdot.org/article.pl?sid=03/04/18/1929220 ) about how the people who maintain the UTC time standard are thinking of abandoning leap seconds.
They periodically insert a leap second so that UTC time doesn't diverge too far from TAI (atomic clock) time. A TAI day is precisely 86400 (that's 60 x 60 x 24) seconds long; but the Earth rotates in about 86400.002 seconds, plus or minus some wobble. The leap seconds mean special-purpose code in the operating systems and the libraries and timekeeping software, and are a bit of a pain. The whole reason they're there is so that official clock time keeps exact pace with the apparent motion of the Sun in the sky.
A particularly good explanation is here:
http://space.mit.edu/URSI/lsappendix3.html
I have another solution to what to do about UTC diverging from TAI time. The whole problem is really that the Earth isn't rotating at the precise speed that we think it ought to. Therefore we should take measures to adjust it.
There would probably be unacceptable consequences to the obvious solution of placing large rocket engines at the Equator -- noise, pollution, and the fact that the rocket plume would be absorbed by the atmosphere, thus cancelling out most of the effect that it would have on the earth's rotation, due to the Law of Conservation of Angular Momentum. Repealing the Law is also an unattractive alternative, due to the objections of world environmentalists and gyroscope makers.
But we're already working on skyhooks, which are geosynchronous-orbiting satellites with tether cables that reach down to the Earth's surface; also known as "Space Elevators". Why not simply attach a rocket engine to the skyhook? Push on the skyhook, which then pulls on the Earth through the cable.
Also, we could just install large, massive, continuously-operating merry-go-rounds at the North and South Poles. The merry-go-round would also serve as a tourist attraction. Also, as the merry-go-rounds would have to go faster and faster in order to keep providing the stabilization, the excess angular momentum could be bled off by using the merry-go-round to fling payloads into orbit. As a bonus, the resulting trajectories would be highly inclined polar orbits, which are ideal for spy satellites.
Linear-acceleration mass-drivers at the equator are another good idea. Much like locating the Kennedy Space Center in Florida, it lets you combine a beach vacation with your trip to the shrine of space exploration, and lets the astronauts play golf.