Garrett Lisi has an exceptionally simple theory of everything. He explains it in about 20 minutes without any equations and with very beautiful images of the E8 model. You can watch his explanation below.
He constructs a visual representation of the mathematics describing everything (that is General Relativity Theory and Quantum Physics which essentially describe everything but don't quite agree leaving several little holes in the overall understanding of everything) and using his 8 dimensional representation of particles and forces he predicts certain new particles that must exist. He awaits the findings of the Large Hadron Collider at CERN to see if the results support or refute his theory.
Lisi was awarded a grant by the FQXi foundation in 2007 to extend his research. The visual patterns illustrated in the talk look very similar to feedback patterns which can be produced in video systems. The very nature of these patterns lead me to feel that he is on the right path. Experience to date tends to suggest that things which are beautiful and simple tend to be good descriptions of the underlying reality which we are trying to understand. It may be a subjective thing but since we are a product of the universe it would make sense that the things which resonate as the most beautiful and harmonious would probably be the things that are most all encompassing and relevant.
You can find out more about Garrett by visiting his web space at http://sifter.org/~aglisi/