The innovation and engineering fest at Liberty State Park in New Jersey yesterday, billed as the union of the smart and useless, was a blast, as usual. Plenty of Segways around, including the new four-wheeler. Talk of personalized medicine, love of eating insects, new cosmic theories like the Big Splat, lots and lots of robots and the awesome eight-foot multitouch screen from Perceptive Pixel. And it was a blast literally. Here’s footage of the jet bike built by the good people at Brooklyn art collective the Madagascar Institute. It took two leaf blowers to prime the pulse-jet rocket in the back but, once the bike fired up, it was good and loud, and joyfully useless.