Tatiana Maslany's performance in Orphan Black, in which she plays clones with wildly varying personalities, has received widespread, well-deserved acclaim. Pair her skills with some really neat technical wizardry, and you get this video, which shows the making of a scene in which the actress, playing four different people, dances with herself. I keep watching this and picking up on little subtleties, like how Jordan Gavaris (Felix) and Maslany interact with personas who aren't even in the shot at the time. The blocking required to pull this off is nothing short of astonishing.
NOTE: The mere interaction of some of the clones in this scene will be a spoiler of sorts, so watch at your own risk.