It doesn't have to be NPC activity either, the Fallout games have all kinds of quirky, semi-hidden little locations for players to stumble upon if they happen upon the entrance. Sometimes they contain stashes of ammo or a particularly rare gun, for example, but more often than not we like them simply because they make us feel like we've discovered something no-one has.
Mostly though, these random encounters and hidden locations aren't in anyway connected to the main quest, which is crucial. They make the world feel lived and give the player a sense of being a part of something bigger rather than being the centre of the universe. We want to see loads of them in Skyrim; big and little, epic, emotional, funny and quirky - more is definitely more.
Oblivion mods, courtesy of those clever bedroom programmers, added the ability to slice and dice from the loft heights of your trusty steed to Elder Scrolls IV, but we think this time around mounted combat should be in the mix from the get go.
Depending on the mod, we've been able to trample foes or zap them with a spell while horsing around on a horse and we think Bethesda has the ability to take this a whole lot further.
And, since dragons have been announced for Skyrim, by "a whole lot further" we're thinking about soaring through the skies on dragon back, casting spells through the clouds as we pursuit an enemy. From the little bits and pieces we've seen of Skyrim so far, it's looking visually enchanting and we think that some sky-based combat would not only make for an exciting and freeing mechanic, it'd make for some epic and beautiful scenes as well.