Very nice TED presentation by an interesting character. This is strongly reminiscent of some ideas I learnt from a guy called Tony Smith in the late 90s. You can find his wild, wonderful, wandering website (nice alliteration?) archived at "Tony's home" . My views at the time were that I was nowhere near adequately qualified to understand a lot of the physics or assess its value, but that the mathematics is so beautiful there has to be some truth in there. The Clifford algebra stuff in particular is highly compelling, and surely must be genuine.
[Looking at the citations for the first of Tony Smith's arxiv publications , I see Garrett Lisi at the top, which confirms the connection I guessed at. I would guess that Lisi was heavily influenced by Smith. One thing they have in common is being kind of mavericks outside the mainstream particle physics establishment. In fact, Tony Smith eventually got banned from posting on arxiv, ostensibly because he had left academia, but the story reads like some sort of fight against the establishment. 
Again, I am not really au fait enough with the mainstream views on superunification to know how much of a conflict there might be between the views of Smith and Lisi and those that are considered mainstream. I believe Tony Smith was not very positive about string theory, and Lisi also seems to dislike it, but I believe it is more likely that string theory and the E8 TOE are different ways of viewing the same thing].
Interesting theory created by Garrett Lisi:
http://www.ted.com/talks/garrett_lisi_on_his_theory_of_everything.html
http://en.wikipedia.org/wiki/An_Exceptionally_Simple_Theory_of_Everything
http://www.science20.com/quantum_diaries_survivor/garrett_lisis_new_e8_paper