There was a leap second June 30th. And while there's not the Y2K-scale of disaster being predicted for it, there are probably going to be a few problems. Here's why computers have trouble with something that should, in theory, be pretty simple.
Explosion at video time 23:35. SpaceX CRS-7 was a private American rocket cargo resupply mission to the International Space Station, contracted to NASA, and launched and failed on June 28, 2015. It exploded 139 seconds into the flight, just before the first stage was to separate from the second stage.