I have been working on a class of browser-based applications which don't require a server.
Calling it PAPPADOM = Portable Application Providing Persistence Atop DOM (Document Object Model)
PAPPADOM is a package consisting of
* Miscellaneous UI components - menubars, menu etc
* Persistence - save stuff
* Open Data - data is stored within the HTML file and hence is accessible.
Neptuner UBoat: http://neptuner.googlecode.com/files/demo_uboat_neptuner_0_20.zip
Just a fancy name...