Really, do I need to say anything else about this game? Its vast, beautiful, immersive, and incredibly fun to play. Pick a direction, start walking, fight some monsters, explore the landscape, and go on spontaneous adventures in the land of fantasy vikings and giant dragons and barbarian bandits and angry Romans. Find a guild or an NPC in a town and discover an awesome quest to go on to find loot. Go home, craft weapons and armor to make the Daedric Princes themselves flush with envy. And when you have time between all of that, find a spot with good view, kick back, relax, and look at the sky and the horizon, and be awed by the world around you.
Then get eaten by a bear, because this is Skyrim, bitches.