Theoretically, since
light bends when near a
black hole, if you constructed a hollow
ring around it near the
event horizon you would be able to look down the tube and see your own back.
Hmmm, since someone here also said you can give a black hole a charge, perhaps you could "catch" a black hole and use it for a power source, similar to using a field to suspend anti-matter. Perhaps you could use it to propel a ship. I wouldn't want it orbiting the planet, though. I'd hate to have an "oops" that ate the Earth.