Through event binder, I can invoke another controller action and update the Dom tree with the new view, however the URL in the address bar does not change.
Is there an API that I can call to update the URL so it will become bookmarkable?
Mojito doesn't do this today -- you'll have to provide your own solution. We're looking at how to add this feature to Mojito, but don't have a plan yet (and thus don't know when it'd happen).