Austin Granger’s 450-foot K’nex track. (via)

Amazing. Can’t wait to show this to my kids. And here’s an interesting exchange in the YouTube comments for this video:

Why should someone spend his whole money for something useless like this? Why should someone spend his whole freetime for something useless like this? Why should someone make his bedroom useless for something useless like this? And many more useless questions are running around my brain…
– binimszueriidschuel

The money I’ve made since I uploaded this video just 4 days ago has paid for the cost of the machine 5 times over.
– austron (Austin Granger, the builder)