Leap Second
Problem
My nasty java app is eating up all the CPU it can get. (Possibly sharing with something else equally unlikely that is eating the rest up -- in my case, milter-greylist.) This CPU consumption started at the moment of a leap second.
Discussion
There's a bug in either ntp or some versions of the kernel
(http://lwn.net/Articles/504658/)
that is causing some classes of applications to freak out.
Solution
service ntpd stop; date -s "`date`"; service ntpd start
Everything should be happy again.