Check Out Acoustic Levitation in Action
From the YouTube page of Japanese scientist Yoichi Ochiai (PeekYou profile here), comes this genuinely, very cool clip.
It demonstrates the experiments of Ochiai — along with fellow scientists Jun Rekimoto and Takayuki Hoshi — in employing sound to suspend objects in air; or, if you prefer, levitate them.
The WikiPedia article on the phenomenon being explored can be found here. But more fruitful still, in the quest to learn more about what you’re seeing, would be a visit to Ochiai’s PeekYou profile; where you’ll find links to further videos, numerous articles, as well as websites and social pages (albeit largely in Japanese).