John Lennon's "Imagine" - a guitar lesson for strummers of all levels. Includes an F chord grip (Fmaj7 actually) far easier than the dreaded barre.
How Dartford Powered the British Beat Boom, a BBC documentary on the history of Vox guitar amps, played by the Beatles, Rolling Stones, Shadows and Queen. Part II
Guitar String Oscillations via iPhone - your physics lesson for the day.