FreeWRL is an Open Source, cross platform VRML2 and X3D compliant browser, with script, SAI and EAI support. Platforms supported: Linux and other Unix-style platforms; Mac OS/X; Windows. Support for mobile platforms (iOS, Android, QNX) is under development.
Ketu is a browser plugin (Firefox, Mozilla, IE) that allows Web developers to integrate Eclipse/SWT based UI components into Web pages, similar to Java applets or Flash movies.
Water: a fast, secure, dynamic OO language and database. Water is an all-purpose language (and meta-language) that runs Web applications in the browser or server-side. Water is compatible with .NET, Java, and C on Windows, Linux and Mac OS X system.
Geedot aims to be a lightweight, fully (and only) HTML 4.01 and CSS compliant and functional web browser for X. It uses the gdtoolkit widget set which is very fast and lightweight - yet also infinitely and easily expandable.