Ruby just got support for Native Client.
Google Native Client (NaCl) is a sandboxing technology for running a subset of Intel x86 or ARM native code using software-based fault isolation. It is proposed for safely running native code from a web browser, allowing web-based applications to run at near-native speeds...
This is pretty exciting. This means you can start running Ruby code in the browser.
In the next couple of years the lines between "web technologies" and other development tools are going to get more and more blurry. Really exciting possibilities.