Turbo Codes

In the mid-1990s, an earthquake shook the digital coding
landscape.

A pair of French engineers - outsiders to the world of coding theory - astonished the insiders with their invention
of what they called turbo codes. For a given transmitter power, digital "error correcting" codes could be sent over a noisy communications channel at about twice the previous speed - and moreover the data could be sent within a hair's breadth of the "Shannon's limit" - the maximum theoretical speed possible.

In the past couple of years, turbo codes have found their way into millions of mobile phones, enabling users to send audio and video clips more efficiently than ever. Turbo's new cousin, LDPC codes, have become the new standard for digital-satellite television. Hundreds of research groups are studying potential applications of the two kinds of codes at universities and industry giants including Qualcomm, Sony, Motorola and Samsung.

Turbo codes were invented by guys who didn't know that
devising such efficient codes was supposed to be hard. "The thing that blew everyone away about turbo codes is not just that they get so close to Shannon capacity, but that they're so easy. How could we have overlooked them" says one of the sources quoted in this fabulous article from Science News: http://www.sciencenews.org/articles/20051105/bob8.asp