There are a few web applications I'm interested in, and projects are available in the area. Most of these will be Ajax-based projects, possibly using the PyJamas framework (Python tool similar to Google Web Toolkit), or directly in JavaScript/ECMAScript.
Some ideas:
A non-
WYSIWYG editor (for code or LaTeX) with features similar to
Google Docs. This project requires the development of a PyJamas or GWT class to support more flexible rich text areas.
Syndication of transport service information from different companies (e.g., integrating local transportation and national railways to get a more complete travel planner in the Milan metropolitan area). A first version of this project has been developed; extensions are needed to make it complete and usable (e.g., allow the user to specify additional constraints or take into account special conditions such as interruptions on a given line or bad weather).
Using web workers to handle on the client part of the computation for the above-mentioned issues.