One of the hot new theories in theoretical physics is Loop Quantum Gravity (LQG). The new scientist has an article, Did our universe exist before the big bang? that discuss this radical theory. Basically it bridges the gaps between quantum mechanics and general relativity by proposing a that the fabric of the universe is woven from quantum gravitational field lines (yeah, read the article).
The idea of the bouncing universe had always made more sense to me than that of endless expansion and a energy death. Basically we are talking about a big crunch with a rebound, they even talk about the possibility that not all information would be lost at the end of the contraction phase (we’ll see about that).
How would this theory work with the possibility of the multi-verse? Could this theory be used to explain reincarnation? How would earlier and later universe differ from our own? Lots of interesting questions to ponder.