It all started like this:
GOD (which stands for Good Ol' Deity, obviously an experimentalist) decided to do an experiment.
"Bang!" He said, and there was a bang. A big one! However, since He had neglected to make a place for the big bang to go, it was hard to tell it had happened.
That's when GUT (for Grand Unification Theorist) tapped Him on the shoulder and reminder Him, "If you had come to all my lectures, you'd have remembered to create spacetime first." She was always pestering Him to think before acting. Typical Theorist.
"I was just getting to that," He said, and created spacetime. Unfortunately, He created it with only one spatial dimension, which made it impossible for anything to get past anything else.
GUT waited patiently for GOD to figure it out on His own, but He could tell She was rolling Her eyes mentally. "Hmm," He said, "needs some more dimensions..." and created another 22 of them.
"Whoa!" said GOD, "Where did everything go?"
"Too much room," said GUT helpfully. "Why don't you curl some of them up to compact the space? You can still make strings in all 23, but let the strings bounce around in a more comfortable number of dimensions."
With much muttering, trials and errors, GOD finally converged on three spatial dimensions, but He forgot to keep time uncurled, so there was nothing actually happening.
GUT just stayed quiet until boredom acted as a reminder and GOD uncurled time.
Then things got busy.