Ka is a show at the MGM Grand in Las Vegas with an emphasis on aerial acrobatics like no other show I know of. $225 million dollars was spent developing a custom built theater with seems to have no floor but only cat walks and aerial platforms.
The New York Times Travel section says:
The story is by turns funny, tragic, and whimsical. There are at least two moments that are nothing but simple stagecraft and yet are exquisite, among the most memorable of any current Vegas show. The theater is cavernous, but extensive catwalks and other staging tricks mean that those in the back won’t feel far from the action. It might be too long and intense for younger children, but older ones will be enthralled — and so will you.
This TechCrunch article describes the marvelous technical achievement.
Due to the speed in which artists fall from the decks, an array of airbags had to be used en lieu of traditional nets alone. These airbags sit atop two nets, which at times are 70 feet (21 m) below the point the artist begins the fall. The airbags contain individual cells which can inflate and deflate independently. In case a power outage occurs, each airbag has its own uninterruptible power supply which can last up to 30 minutes.
This video briefly describes some of the incredible moving platforms in the theater.