You can think of the event horizon as the mouth of the black hole. Once something passes the event horizon, it's gone for good. Once inside the event horizon, all events (points in space-time) stop, and nothing -- not even light -- can escape. There are two types of black holes:
The Schwarzschild black hole is the simplest black hole, in which the core doesn't rotate. This type of black hole only has a singularity and an event horizon.
The Kerr black hole, which is probably the more common form in nature, rotates because the star from which it was formed was rotating. When the rotating star collapses, the core continues to rotate, and this carries over to the black hole. The Kerr black hole has the following parts:
- Singularity - the collapsed core
- Event horizon - the opening of the hole
- Ergosphere - an egg-shaped region of distorted space around the event horizon (caused by the spinning of the black hole, which "drags" the space around it)
- Static limit - the boundary between the ergosphere and normal space
Black holes won't consume everything around them. If an object passes into the ergosphere, it can still be ejected from the black hole by gaining energy from the hole's rotation. However, if an object crosses the event horizon, it will be sucked into the black hole and never escape. What happens inside the black hole is unknown.