Native Client

http://code.google.com/p/nativeclient/

Native Client is an open-source technology for running x86 native code in web applications, with the goal of maintaining the browser neutrality, OS portability, and safety that people expect from web apps. We've released this project at an early stage to get feedback from the open-source community. We believe that Native Client technology will help web developers to create richer and more dynamic browser-based applications.