From Marc Rober on YouTube.com:

I fulfilled a 3-year long dream to create a dartboard where you get a bullseye every time thanks to some engineering. Basically, you throw a dart and then a Vicon motion capture system tracks the dart in the air. We use those x,y,z positions in Matlab to predict where the dart will land using some regression analysis. Once we know where it will land, we move the board to the right spot using 6 stepper motors that attach to the back of the board using fishing line. All of this happens in 400ms or so. Then we took it to a bar to see what people would think of it (SPOILER ALERT: they liked it)