Nimbus Flyboarding's personal watercraft contraptions are pretty much designed for one thing: delivering an adrenaline rush. The jetpack-like devices propel users with a powerful stream of water, sending them diving headlong beneath the water or soaring up to 60 feet in the air to hear the secret songs birds sing when they think they're out of human earshot. Though the whole thing can seem a little overwhelming at first, beginners shouldn't fret: according to the owner of Nimbus Flyboarding, most people pick up the basics within minutes.