Phil Plait at Bad Astronomy gives us the run-down on Martin Bojowald's Big Bounce Theory of how our universe came into being:

What Bojowald’s work does, as I understand it (the paper as I write this is not out yet, so I am going by my limited knowledge of LQG and other theories like it) is simplify the math enough to be able to trace some properties of the Universe backwards, right down to T=0, which he calls the Big Bounce. The previous Universe collapsed down, and "bounced" outward again, forming our Universe. No doubt the physical aspects of this previous Universe were somewhat different; the quantum uncertainties at the moment of bounce would ensure that. It may have been much like ours, or it may have been quite alien. In his equations, it’s the volume of that previous Universe that cannot be determined. How big was it? It may literally be impossible to ever know.

In the traditional model, talking about anything happening "before" the Big Bang is meaningless. Time doesn't really start until the the Bang occurs. Not that that stops people from talking about it anyway. I know that I, for one, tend to assume that if there are multiple universes, there must be some kind of larger time that could be observed in the relationships between them -- if such relationships ever could be observed! The Big Bounce is intriguing, but if not quite weird enough for you, Plait also directs us to some information on Brane Theory:

For an eternity, our universe lay dormant—a frozen, featureless netherworld. Then, about 15 billion years ago, the cosmos got an abrupt wake-up call.

A parallel universe moving along a hidden dimension smacked into ours. The collision heated our universe, creating a sea of quarks, electrons, protons, photons, and other subatomic particles. It also imparted microscopic ripples, like ocean waves crashing on a shore.

These ripples generated tiny fluctuations in temperature and density, the seeds from which all cosmic architecture—from stars to gargantuan clusters of galaxies to galactic super clusters—ultimately arose.

So in this model, if that other universe had never slammed into us, our universe would never have been anything more than a sort of potential universe. Raising the question of how long (in that larger, inter-universal time) did we have to wait before coming into existence?

Just a little something to ponder as you start your week.