FlippyCat's animated 3D domino depiction of the comet-strike extinction of the dinosaurs is both poignant and exciting, and the setup/blooper-reel that follows the main action is a real nail-biter.
Also known as domino-saurs
This took 38.5 hours of setup time, over about 2 weeks.
This project contains several smaller projects that I have wanted to do for a long time...the earth being hit and spreading out (since I did this with flags), the eggs revealing something behind them, a fossil/skeleton and a domino-saur!
The Fall of the Dinosaurs (Thanks, Fipi Lele!)