Via Octopus Dropkick and Pixelsumo:
"The 1K Project II is created by an artist called Blackshark... using the physics based driving game Track Mania. 1000 replays were recorded, then played back merged together using the reply editor. The result is a polished video of flocking swarming cars."
I found this yesterday afternoon and watched it enough times to have had a dream about it last night. It reminded me of being stuck in the backseat of the family Oldsmobile as a child, with the only escape offered by imagining a physics-defying car speeding alongside us, jumping trash cans, executing controlled skids, and doing flips in the air with hypnotic fluidity and grace. This is a bit like that same mental escape -- copied and pasted into the same part of your brain 1000 times over.
[Stream video] (high quality)
[Download 28 MB video](kind of bit-mappy, but will suffice if the streaming link goes dead)