So actually an event horizon is something that sucks away time?
Hmmm....I see. According to our common sense, you would definitely think space and time are two separate things. Space are even and time is absolute (independent of everything). Such ideas are formulated and strongly believed in the earlier days. Isaac Newton wrote these as axioms in his Principia, which became the cornerstone of the classical physics. We call such space Euclidean.
But Einstein's general relativity tells you something different. Space and time are inseparable. Space have 3 dimensions (x, y and z) and time has another dimension (t). Together, they are known as the four dimensional space-time continuum. This is because of the fact that the only constant in reality under all conditions is the speed of light. Think, if you shoot a missle at the ground, its speed will be 500m/s. If you shoot it on a fighter jet with speed 300m/s, your missles with get a net speed of 800m/s. Not so for light. They will always be the same no matter how you measure it. This results in lots of funny phenomena if you travel near the speed of light. Hence, measurements must be done based onthe speed of light. Measurements for distance and mass should also be adjusted according to the set of relativistic formulas.
He also solved the mystery of gravity. Think: why is the gravitational mass the same as inertia mass? They have no reason to be the same! The consequence is that all things have the same gravitational acceleration. Why would a feather fall as fast as a coin in vaccuum? That suggest that they gravity must be something external, perhaps a property of space. He eventually solved this using extremely complicated mathematics and ideas from the mathematian Riemann and Einstein's ex-prof Minkoski(Einstein used to look down on him : p ). The solution turned out to be the four dimensional space-time fabric I mentioned above.
Cuvature of space-time = G (Mass density of matter in space-time x c)
In this paradigm, you can think of space as an invisible rubber sheet that has been stretched tight. Now, imagine a star as a ball bearing placed on the rubber sheet. You will notice that the sheet formed a depression. Now, if you put a smaller ball (planet) into near the area of depression, the ball will fall towards the centre, which is the star. This is roughly the idea of general relativity. If you push the smaller ball tangential to the perimeter of depression, at the right velocity, it will go around the ball bearing, hence the revolution of planets around the sun.
Now, coming back to your question. A black hole is something with such a steep curvature that you can imagine it as the rubber sheet with something so heavy that it stretches almost vertically downloads. (Of course, space-time curvature don't break like the rubber sheet). So what happen is that if it is so steep that photons cannot escape from it? Then what is happening inside the event horizon (Schwarzschild radius to be precise) cannot physically affect anything outside (based on locality principle, which is later proven to be flawed by EPR paradox). If we measure the time flowing inside, we must first find a reference. Taking earth as the reference, since what is happening inside can never affect what is outside, the time taken inside for a unit time to pass in the outside world is infinite. Hence, time actually stops right at the Schwarzschild radius.
At the moment, singularities still cannot be effectively described by our physics. People are looking towards quantum gravity to explain it. Roger Penrose even believes it can solve the "hard problem".
Physics is also filled with symmetry: eg. matter and antimatter. There are speculations of white holes that spew forth matter from a singularity. This is a time reversal of the black hole phenomenon. Of course, as it is only moltivated by symmetry and is still not directly observed.