Google introduced a new project called Native Client, it enables web developers to run x86 code in web applications, similar to Microsoft's ActiveX but a bit more open. You can find more info at Google Code.
Native Client is an open-source research 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, research stage to get feedback from the security and broader open-source communities. We believe that Native Client technology will someday help web developers to create richer and more dynamic browser-based applications.