The health care industry is no stranger to mergers and acquisitions, but in a span of roughly two weeks last month, we saw three huge acquisition announcements that were anything but typical. CVS plans to buy Aetna for $69 billion in cash and stock; UnitedHealth Group's Optum unit will acquire DaVita Medical Group for $4.9 billion in cash; and Humana, along with two private equity firms, has agreed to buy Kindred Healthcare for $4.1 billion (Humana will pay $810 million for a 40% stake in Kindred's home health care business).