Hearthfire: DLC

Hearthfire is an official plug-in for Skyrim. The plug-in had an exclusivity period of one month on the 360, similar to Dawnguard.
With this official add-on to The Elder Scrolls V: Skyrim, you can purchase land and build your own home from the ground up - from a simple one-room cottage to a sprawling compound complete with an armory, alchemy laboratory, stable, garden, and much more. Use all-new tools like the drafting table and carpenter's workbench to transform quarried stone, clay, and sawn logs into structures and furnishings. Even transform your house into a home by adopting and raising children.

Hearthfire Items — New items added by the plug-in, including apparel, books, building materials, weapons, and more.
A house built by the player in Falkreath Hold
Ability to build and customize your own house.
You must purchase the land and use raw materials at a drafting table and carpenter's workbench to create rooms and furniture for your house.
Equip your home with arcane enchanters, armories, forges, gardens, libraries, shrines, stables, taxidermy, and more.
Three plots of land are available for purchase, in Falkreath Hold, Hjaalmarch, and the Pale.
The structure of each house consists of stone, clay, and wood.
Ability to adopt up to two children, who will move into your house.
Interact and play games to raise your new family.
Allow your child to keep a pet after it follows them home. Some creature followers can also be kept as a pet.
If you wish to adopt children without moving into a new home, you may add a child's bedroom to an already purchased home in a major city.
Ability to hire staff:
Turn followers into stewards, who can supply you with housebuilding materials, furnishings, and staff.
A carriage driver who can take you to small settlements as well as major cities.
A personal bard to perform at your home.
New activities, such as baking, beekeeping, farming, and fishing.
Requirement to protect your house from various enemies such as bandits, dragons, giants, skeevers, and more.
Available Houses

All three of the new pieces of property can be purchased for 5000 gold.
Heljarchen Hall — Located in the Pale, this plot of land may be purchased from the Jarl of Dawnstar in the White Hall. You will have to complete the quest Waking Nightmare, and then the favor quest Kill the Giant before being allowed to purchase the property. (Note: This favor has a prerequisite of being level 22.) If you are thane of the hold, you will be appointed a housecarl named Gregor.
Lakeview Manor — Located in Falkreath Hold, this plot of land may be purchased from the steward of Falkreath in the Jarl's Longhouse. You will have to complete the quest Kill the Bandit Leader before being allowed to purchase the property. (Note: If Siddgeir is jarl, this requires completing his version of Rare Gifts first, which cannot be started while another version of the quest is active.) If you are thane of the hold, you will be appointed a housecarl named Rayya.
Windstad Manor — Located in Hjaalmarch, this plot of land may be purchased at Highmoon Hall in Morthal, either from the steward Aslfur if Idgrod Ravencrone is still the jarl, or from the new jarl, Sorli the Builder, if the Stormcloaks have control of the hold. You will have to complete the quest Laid to Rest before being allowed to purchase the property. If you are thane of the hold, you will be appointed a housecarl named Valdimar.

Bibliography:
http://www.uesp.net/wiki/Skyrim:Hearthfire