It's called Blu-ray/DVD hybrid disc. It features a single-layer of Blu-ray on one side and a standard DVD on the very same side. So you won’t have to flip it around.
And as you are used to hearing, it’s appearing first in Japan, with something called Code Blue emergency helicopter doctor Blu-ray BOX as the first hybrid title.
Until now there's no word yet on when or if we will see this technology in the states, but a little backwards compatibility never hurt anybody.
We gotta get that one guys...