I have been using Opal with the Vienna front-end framework and have really enjoyed it. Opal allows me to write ruby on the front-end and the back-end.<p>Many times I have tried to get excited about javascript, but just can't do it. In the end, I love ruby and can't force myself to love javascript.<p>Opal has been surprisingly stable and it allows me to run ruby anywhere you can run javascript. Vienna is still very alpha, but still gets the job done. The author says they are working on things such as two way data binding (the part I love about Angular)<p>In the end I hope that Opal becomes the standard for Rails, but even if it doesn't, I plan on using it for all my next projects.