Entitled "Hearthfire," this DLC allows you to buy a plot of land and build your own house. No, I'm not joking, this is actually a premium DLC add-on.
Don't believe me, check out the official trailer here or below.
I can see how this would appeal to some players, but those players aren't me. I can think of far better things to spend 400 Microsoft Points on.
I also think it very odd that you can adopt children but you can't actually "make" a baby with your spouse. This is a Mature rated game, after all.