Way back when in 100 BC, Greek engineers developed a machine called the Antikythera mechanism that allowed them to predict celestial going-ons such as solar eclipses. Turns out it was pretty accurate, though it was lost at sea for a good 2,000 years. Now, one man has created a faithful replica of the thing using only Legos.
That one man? Apple software engineer Andrew Carol. He used 1,500 Lego Technic pieces (which are more advanced than you're usual pegs-'n'-bricks) to construct the 110 gears and four gearboxes that run the machine. Each box is its own little piece of computing hardware, crunching one equation per box, and when you input some calender data into it, it should be able to tell you when the next solar eclipse will be.
See the Antikythera mechanism in action in the video below, complete with overly epic music.