I'm going to sort of expand on what JHorton said. Hopefully, I won't slaughter this too much. It's theoretical math and I am just starting to grasp the concept. I've been teaching myself using the Matrix and Run Lola Run as my way to view the concept. Bear in mind, I have taught all of this to myself. If I am off base and you know it I would LOVE the input.
First, you have to look at existance as a 3 dimensional infinite grid. There is energy that moves through the grid. These energies are time, space and conciousness. Because these are all infinate anything is possible. For the sake of this, I am going to take a small section of the grid to work with. First, space. Space will fill up a section of the grid and make up the area of the Matrix. Time will run from the creation of the Matrix to the destruction of the Matrix. Say left to right over the section of the grid filled by space. Now you need to add conciousness. Conciousness will be human thought. It will run from top to bottom through the section of the grid. You now have time and conciousness intersecting in a set area of space known as the matrix. Events occur only at points of intersection.
The One is a conciousness at the point of a certain event. The One is created only at this event. Until this event The One does not exist. Every conciousness is a possibility. The closer you conciousness is to the time space intersection the more of a potential you are. In the first movie Neo and the other potentials are the ones closest to that intersection. Any one of them could be The One. The Oracle tells Neo he is not The One because at that time no one is. The event that creates The One has not occured. The kid with the spoon understands how the Matrix works. He uses the spoon to explain the concept to Neo. The spoon represents the future event. Thus, it does not exist. There is no spoon. (yet) He tells Neo not to try to bend it as that is impossible. You can not change the future from the now. He tells him to realize that it is not the spoon that bends only himself. His choices can lead him closer or further from the event and is what changes the outcome. Both the Oracle and the kid are teaching Neo how the Matrix works.
In the second movie Neo has learned more about the grid and how to maipulate it.
Neo has now also begun to "see" possible events on the grid. But, he is still having trouble understanding that they are only possible. Choices, his and those of others can change the event. When he sees Trinity die he is seeing a possible future. The kid with the spoon sees more including the possible choices for Neo. He is trying to help Neo make the right choice. But, he can not tell him what choice to make as then it isn't actually a choice. Instead he sends the spoon. The spoon this time represents the event of Trinitys death. In other words, don't try to stop the event before it happens, only try to move yourself towards the event. Neo doesn't get it.
He tries to alter the event by asking Trinity not to go. He has effectivly limited her choices at a point in time this moved her conciousness closer to the event. Since Trinity was forced to stay her next possible choice was to stay put or go help. She chose to help. Again she moves closer to the event. If she had gone on the original mission, she may have been on another part of the grid and her choices might have kept her away from the event.
When Neo meets the Architect , the Architect explains the Matrix to him in more detail. On one level of the grid are the sleeping humans. They are limited to certain choices because they don't know any others exist. The ones that get woken up now have more choices and can potentialy move through more of the grid. The more you learn about the Matrix the more choices you have. The more choices the more movement.
Now, human conciousness is bound by certain perceptions. Time is linear. Conciousness can only be in one place at one time. No two of the same energy can be in the same space at the same time. Physical is real. This limits their choices such as jumping from one point to another. The programs are are not bound the same as the humans. This why the agents can jump to an event and force the occupying conciousness out. Smith, is bound by even less. He has figured out that his conciousness can be in more than one place at one time.
If a conciousness were to realize it was just energy, not a specific energy it would have no limits at all. Of course, this leads to you are everything and everything is you. This means everything is a single point. Existance becomes a cingularity and collapses in on itself. Once on the other side it is all possibilities again. Chaos to order to balance and back to chaos again.
This is the basis of Buddhist thought as well.
I could go on for hours.....
I hope this is at least a bit understandable.
In Run Lola Run, they have figured out how to move their conciousness on the time line. But, they can only move as far back as when they learned of the event they are trying to change. That's why she starts at the call. She then moves through the grid looking for choices that will lead them farther away from the the event. He is doing the same.