There are a huge number of fascinating documentaries available through Google Video. Here are some of my favourites:

• The Six Billion Dollar Experiment covers the search for the Higgs boson (the so-called ‘God Particle’) at the Large Hadron Collider at CERN.
• Time Travel discusses the scientific basis for different methods of time travel.
• The Death Star is an analysis of the most extreme objects in the Universe: so-called ‘hypernovae’.
• Fission is the New Fire is a talk given at Google HQ by Rod Adams about how totally awesome nuclear power is.
• Fermat’s Last Theorem is based on the book by Simon Singh and tells the story of how Andrew Wiles solved the “greatest mathematical problem of all time”.
• Prospects for Extending Healthy Life … A Lot is a talk by Dr Aubrey de Grey on the prospects for halting the aging process. (Worth watching just for de Grey’s amazing science beard.)
• Last Days on Earth describes seven scenarios in which life on Earth as we know it could be extinguished.
• The Enemies of Reason (Part 1 | Part 2 | Part 3) lets Richard Dawkins loose on those who choose to ignore the rigours of logic, observation and evidence.