Almost everyone wishes they had the power to make objects float in mid-air, but perhaps technology is getting to a point where we don't have to wish anymore.
Ultrasound researcher Asier Marzo came up with a home-made levitating machine that can cause light objects smaller than 4mm to float in mid-air. The secret is a steady stream of 40kHz sound waves that suspend objects between two surfaces riddled with transducers.
Marzo's contraption works with both liquids and solids, but the transducers require a specific voltage depending on what he wants to levitate. Merely adjusting the energy makes the device a versatile levitation machine, yielding hours of fun.