Microscope describes itself as "a fractal role-playing game of epic histories." This is a big claim, perhaps insanely ambitious, but Microscope might just be able to pull it off. I haven't had a chance to play Microscope, so this based just on reading the text, but that said:

I've theorized roleplaying games as about Structured Negotiation. In that regard, Microscope gives you a very powerful and elegant way to narratively generate histories. The nested structure of Period-Event-Scene intuitively let players control the scale of the game. Scenes, the core roleplaying bits, are cleverly framed by use of a Question which must be decided. The rules themselves give a lot of power to each player in turn, demanding contributions from everybody in the hotseat, and discouraging collaboration and play by consensus. Your epic history is supposed to be a spiky mess.

Where I am less sure about Microscope is it's ability to resolve impasses, when players disagree or have no good idea. The game is a little shaky on how long (in real time) everything is supposed to take. Like most story games, tMicroscope needs a high trust, imaginative groups.

Regardless, I'm very excited to get a chance to play Microscope and see how it works.