This YouTube Video (also embedded below) of Prof. Stephen Curry’s lecture at the Royal Institution is absolutely fantastic. The lecture was delivered in 2013 to celebrate centenary of the discovery of X-ray crystallography. [I guess this was a prelude to the year 2014 being celebrated as the International Year of Crystallography].
In just over 60 minutes, Prof. Curry covers pretty much all the key developments in 100+ years of X-ray Crystallography; he makes effective use of nifty demonstrations (the one with light going through 1, 2, … 6 slits is particularly nice) and informative animations (the one that demonstrates why even the slightest of deviation from the Bragg condition leads to zero intensity). Also, he does not shy away from presenting complicated concepts (such as Fourier Transforms) using a simple (but non-condescending) language.
Finally, the mild bits of humour peppered throughout the lecture are a big bonus!
T.A. Abinandanan 