Roundcube Webmail is a browser-based, multilingual IMAP client with an application-like user interface. It provides the full functionality you expect from an email client, including MIME support, address book, and folder manipulation. High extensibility is granted by the plugin API and the user interface is fully skinnable using XHTML and CSS 2.
Quassel IRC is a modern, cross-platform, distributed IRC client, meaning that one or more clients can attach to and detach from a central core, much like the popular combination of screen and a text-based IRC client, but graphical. In addition to this unique feature, it aims to be a comfortable chatting program.
MuseScore lets you notate and compose music easily with your keyboard, your mouse, or a MIDI keyboard. You can print beautifully engraved sheet music or export it as PDF or PNG. You can play your score, transpose it, and save it as audio or MIDI file. MuseScore also supports MusicXML to let you share your composition with other scorewriters. MuseScore is often advertised as a cost effective alternative for Sibelius and Finale.
KuickShow displays images using all available space, without wasting it with bars or menus. It also has smart automatic zooming which scales images according to size. You can use the integrated file browser to choose images, or navigate through a folder with the mousewheel or the keyboard. It also has fullscreen view and slideshow, and supports a wide range of image formats.
Txt2tags converts a text file with minimal markup to HTML, XHTML, SGML, DocBook, LaTeX, Lout, Man page, Creole, Wikipedia, Google Code Wiki, PmWiki, DokuWiki, MoinMoin, MagicPoint, PageMaker, AsciiDoc, or ASCII Art. It is simple and fast and features automatic TOC, macros, filters, include, tools, GUI, CLI, and Web interfaces, translations, and extensive documentation.
ERDialog is part of a simple Web based framework with Erlang. It is a Web browser interface and system for developing programs using the Yaws HTTP server and Erlang support programs. It will be able to ship applets for installation. Applets for wiki, music playing, and file launching exist now.