The Kalam cosmological argument was popularised by Dr. William Laine Craig as a proof for the existence of a prime mover; a God by which we mean any entity which brought the universe into existence).

I am not persuaded by the argument, but I will put it forward here, unchallenged, because it is more interesting than it first appears.

The premises are:
1. Everything which begins to exist has a cause;
2. The universe began to exist;
3. The universe has a cause

Basically, if there truly is a cause to the universe, one would be hard pressed to believe it has absolutely no God-like properties. At the very least it would, in some sense, need the creative power to create a universe. So if we take for granted that the universe began to exist, it is necessarily finite. But any cause would have to be infinite.
For an infinite entity to create something at some point it would have had to have made a choice to create. There was a point in its infinite lifespan that something within it changed and subsequently the universe was created. Otherwise the universe would have existed infinitely in parallel to the entity, and the entity is no longer even needed.