You will be delighted to hear I have a new proof of the existence of God, which I now present to you.
It is a proof by analogy (Richard Dawkins is quite fond of these; see 'memes').
I had a bathroom which needed to be installed. I was told there was a plumber and that he would come and install the bathroom. I had never seen the plumber personally, nor spoken to him or heard him speak, but I was excited at the thought of the bathroom being installed, and I believed that the plumber would do it.
This is like God. No one has seen God or had a conversation with Him (out loud, in the usual face-to-face manner). However, many of us believe in God.
After a time, I became dismayed at the non-arrival of the plumber. Various excuses were offered by the Chief Builder ('He's sick', 'He went to Thailand', 'He got attacked and his leg is broken in 3 places', 'He was climbing Mount Everest' - I promise you, these are all true things he told me). I began to doubt the plumber's existence.
This is like agnostics and atheists. They say that they have not seen God, so he must not exist. Even though plausible reasons are offered by theologians ('God is invisible', 'Have faith', 'He went to Thailand', 'He'll be along shortly'), still these people doubt.
However. Yesterday I came home and my toilet was installed!!!! Although I still did not see the plumber, it is clear that someone must have installed the toilet. Toilets do not install themselves, even with much prayer. Therefore the plumber exists.
This is like the universe. Universes do not create themselves. But the universe is here.
Therefore God exists.
I am quite pleased with my proof, and confident that it is watertight, unlike my bathroom sink.