Before I start, I should let it be known that I am not a very religious person, and do not claim to have a vast knowledge of religious ideas. This is simply an idea of how the world might work that does not advocate any existing religion.
First of all, everything that goes on in the world, down to you reading this node, is preordained, and predetermined, according to God's grand scheme. So, that means that you have no choice in your actions, to a degree. You can in fact do whatever you want, but if it is not in accordance with God's will, then you will be forced to repeat your actions until you get them right. For example, let's say that you were supposed to save someone's life, but for some reason or another every detail about the situation did not allow you to save that person's life, so you didn't. Because of that, you must now start that day over, and retry that day until you end up saving that person's life. Now, it just so happens that my idea provides an explanation for deja vu, for if one is forced to repeat a given scenario enough times, then one might very well recognize some aspect of that situation, and it may seem as if it had been done before. I realize that this does complicate things when it comes to heaven and hell, (because if you have no choice in your actions, then how can you be judged for them?). In fact, as it stands, this idea, more or less, says that there is no heaven or hell. That is, unless your residence for all of eternity is based on what you do in those days that things didn't work out, and you had to redo.
As I said before, this does not represent any ideas set forth by an established religion, nor am I trying to popularize this idea. Furthermore, I am not trying to debunk any existing religious view of predestination, heaven, hell, or God. This is only an idea. However, I can say that I have received some inspiration from ideas that can be seen in Donnie Darko, The X-Files, and to some degree, Groundhog Day, starring Bill Murray.