We live in a world of analog. Clocks are a great example of how time is continuously changing with nearly infinite precision. However, when you look at a digital clock, there are very specific "digits". (Get it? Digital... Digits...) Using the analogy of clocks, this TutorialCast explains the basic difference between Analog and Digital Electronics. It ends with a slight twist.
Links mentioned in video:
AddOhms Episode 5: http://www.addohms.com/ep5
Adafruit ADXL377 Breakout board: http://www.adafruit.com/products/1413
Arduino (In case you need it): http://www.arduino.cc