Nova - The Elegant UniverseAdapted from a provocative book by Brian Greene, this deeply engrossing documentary -- which originally aired on PBS's NOVA in three parts -- attempts to explain the controversial string theory, a complicated scientific proposal that, in short, posits a single explanation for many of the universe's mysteries. As affable an egghead as you're likely to find, Greene engages an array of physicists in his examination of string theory, which in part blends Einstein's theory of relativity with the complex laws governing quantum mechanics. Although mind-numbing technical terms are kept to a minimum, those of us not conversant with advanced physics might feel a bit lost at times.

Still, the subject is undeniably fascinating, and some of the conclusions are nothing short of mind-blowing: a reasoned, professional discussion of a universe encompassing 11 separate dimensions certainly calls Johnny Carson's "I did not know that" to mind.

In some ways reminiscent of Carl Sagan's Cosmos series, The Elegant Universe is even tougher to get a handle on. But the effort will prove rewarding, especially when you're looking for a way to melt the ice at cocktail parties.

Watch the full documentary now (playlist - 2 hours, 48 minutes)