LOL and there it is, the one comment you just know is coming at some point when you attempt to debate a true believer. Yeah, the Big Bang is a theory because science is willing to accept the fact they don't know everything. Maybe the religious folks should start referring to their belief in god as a theory as well. Would that be acceptable?
Also, claiming that the Big Bang started with nothing shows your complete ignorance of what science has theorized. Additionally, we are able to see the universe expanding along with the cosmic background radiation, both strong pieces of evidence that the universe began as scientists believe. There's also something known as the mixture of elements, a theory that has been confirmed from the observation of some of the oldest galaxies and stars in the universe. In total, there's a mountain of evidence that backs up the Big Bang.
Here's your chance to present your evidence for the existence of a god. Show us what you've got.