Next Action, todo-list tool and great single page application that runs locally
Just take a look at Next Action for example, a Getting Things Done todo-list tracking tool.
Over at TrimPath.com, you'll also find open-source components to build this type of applications. These crazy things include:
- JavaScript Templates, which lets you have template-based programming (like PHP/ASP/JSP) while running in a web browser.
- TrimQuery, a 100% JavaScript query engine that features an embeddable SQL syntax.