This is an idea I came up with a while ago, and I'm not sure I believe it, but I'd like other people's input all the same.  This idea requires some basic assumptions: God exists, and God created the Universe.  I'm using the Judaeo-Christian God and creation account, solely because it is the one I am most familiar with, but I think this may work with other religions, with a little tweaking.

What if the Universe wasn't always the way it was now - what if it is evolving along with us?  Perhaps the Universe was created the way it says in the Bible, but God changed history so that it was created by the Big Bang.  Maybe the World once was flat, but as humanity progressed, God made it round, made the Earth revolve around the Sun, made life come about through evolution, made molecules, atoms, strings, the smallest things in the Universe, and on and on, and caused it all to always to have been this way.

Now, the obvious question if we are accepting this hypothesis is, what would be the point?  Is God just bored?  And I have an answer for that, as well.  God wants us to keep from getting bored.  We all saw what happened the first time: everything was perfect, we didn't need to do anything but keep away from one tree, but we got bored with perfection, and botch it.  So, to keep us busy, and safe from whatever else is out there that is off-limits to us, God is constantly changing reality so we have more to find out, more to discover, more theories to crumple up and throw away to be replaced by new ones, but that were ALL RIGHT at one point or another, all so we don't sit down and think up something REALLY bad.  God may have even taken and implemented some of humanities ideas that were "wrong" at the time, instead of just waiting for us to discover the new Rules, he let us have a hand in making them.