When I was a (younger) kid, I had a Theory of Everything. I have since then thrown away this theory, since it is highly unlikely, but I thought I might post it anyway.
It has been an infinite amount of time since the Big Bang, therefore space is infinite as well. The Big Bing created an infinite number of planets with an infinite number of atmospheres. Basically, every possibility of everything in the Universe was created. On these planets, every possibility of combination of cells were created. The beings that were put together properly AND could live in a suitable environment longer than [insert a number] years lived evolved to live permanently in the environment and grew into beings. Humans are merely one of them, and humans are the only being on this particular planet that were given the ability to think logically and creatively.
Strange idea I had, huh?