Google's beta Chrome 14 includes its Native Client (NaCl) framework under the bonnet. In the past you had to switch on the feature but it looks like it will finally be enabled by default in the next major version of the Web browser.
It has been a rough ride for NaCl has it had some major technical problems, particularly to its sandboxing mechanism. That problem has since been fixed and it now has 64-bit support and experimental ARM compatibility. Google has opened the source code and is encouraging other browser vendors to support the technology, but none have expressed much interest.