I talked a little while ago about the enlightening insight of understanding more about how the next phase of Applications will be "desktop-deployed web applications". This was inspired/aided by listening to the brilliance of people like Matt Webb. Using standardized, hopefully cross-platform technologies, it's possible to develop your application once, and "push" it to any number of devices.
Ajaxian discusses Adobe's new "Apollo":
Apollo is client-based software that will run Flash applications separately from a browser, whether online or offline
The image shows an example travel application developed in Flash, and deployed to a desktop via Apollo. (via Digital Backcountry)
I also saw that Chris Messina is helping out on a project WebKit on Rails, whose goal is to make it easier to deploy Apple's WebKit and also to "come up with new ideas and practices that leverage the WebKit platform". WebKit is an excellent platform to develop desktop web apps, as it can be baked straight into a Cocoa application, but be accessing a "web application" that may be running locally on the users' machine.
rails-app-installer allows you to bundle and install/uninstall a Rails application, including required gems.
$ gem install my_app
$ my_app install /some/path