...The Surul Pattai or Urumi (Spring-Sword in English) is a long, flexible metal blade that is indeed somewhat like the ribbon dancing equipment from gymnastics, though each one typically had 1 to 5 blades, similar to a cat-'o'-nine-tails.
According to a museum curator in India, the sword could also be worn around the waist like a belt. The blades are made of extremely thin, razor sharp metal, with lengths varying from 5ft to 10ft. They were commonly crafted by measuring the armspan of the future user. A blade's width usually ranges from 1 to 2 inches.
It's commonly used along with a shield for self-protection. Like many flexible weapons, you have to maintain its momentum, but because its razor sharp as opposed to blunt (like most flexible weapons), a wielder failing to keep the correct speed, wrist-work and pose could find the Urumi coiling around him- often resulting in decapitation.
For D&D, I'd make it a 1 handed exotic weapon doing 1d4 or 1d6 per blade, 18-20x2 slashing, with a short and long (reach) version. Each blade would require a separate attack roll and do its damage separately- meaningful considering the DR mechanic. Weapon cost would be per blade, max 5 blades. Its structure means it wouldn't have a lot of durability and wouldn't be usable for any of the various special combat maneuvers. Fumbles should do damage to the wielder. Because of their difficult and "customized" crafting, you might want to make them masterwork.
Given that its almost exclusively associated with certain martial arts, you could also make it a Monk weapon.
{The East has a bunch of interesting exotic weapons, like the razor-edged yo-yo (seen in a James Bond movie) and the chacram (made famous by Xena).}
), but fairly comprehensive, interesting, and well, big. 
