For instance, I was traveling on the road around the Imperial City when, from the woods on my left, an Argonian ran across the road, followed by a boar. They then just stopped right there and dueled it out (Argonian lost; wut). Or the time I followed a friendly bandit along the same road all the way to Umbra's hideout, where she slept in Umbra's bed. Or when an old lady pickpocketed all of my potions for seemingly no reason.
They were often enough to keep me on the lookout for one, but rare enough that I pretty much could not get over them when they happened, and I kinda hope that they make a return in Skyrim.