For many American parents, the nest has been anything but empty since the Great Recession disenfranchised legions of millennials and drove them back to the warm, expense-free bosom of mom and dad’s place. But the nation is waking up from its long, nightmarish slumber, according to a report from Harvard University’s Joint Center for Housing Studies, which has projected that millennials will begin moving into their own residences in droves, creating 24 million new households between 2015 and 2025.