NanoraptorI think before we try a Dyson sphere around a star we should start with something small and simple like a magnetar. We can harness some of that magnetic rotor and the Dyson stator can just give us simple free energy
StarkRG@NanoRaptor I'm pretty sure that would either accelerate the Dyson sphere or ringworld until it pulls itself apart, or it'll induce eddy currents that would melt whatever you made it out of.
Charlie Stross@StarkRG @NanoRaptor Not to worry, the magnetic fields are so strong that if you can get close enough to see the magnetar with your naked eyes your eyeballs (and all the atomic nuclei in them, and the rest of your body, and your spaceship) will have been spaghettified.
@cstross @NanoRaptor Oooh, I like spaghetti. Is grated parmesan provided or do you have to bring your own?
@StarkRG @NanoRaptor within a few thousand kilometers of a magnetar you ARE your own parmesan!
@cstross @NanoRaptor Be the parmesan you want to eat in the world.
Cenobyte 
@cstross @StarkRG @NanoRaptor the magnatar's fields are so strong they literally polarize the quantum vacuum. Creates some strange effects!