Can you orbit the event horizon of a black hole?
A black hole is a gravitational warping of the space-time continuum.
The graph above illustrates how scientist believe black holes affect space-time.
No you certainly can't orbit the event horizon.
A black hole is described by a solution to General Relativity.
It is a massive object which has been compressed to the point that it can no longer be normal matter. The inside of a black hole is technically not part of our universe as nothing, not even light can escape once it has crossed the event horizon.
It isn't a black ball as you can't touch it. You can't get near to the event horizon of most black holes without being torn apart by gravitational tidal effects. To an external observer, something approaching the event horizon will never get there. The reason for this is that time stops at the event horizon.