Jitsi (formerly SIP Communicator) is an audio/video and chat communicator that supports protocols such as SIP, XMPP/Jabber, AIM/ICQ, Windows Live, Yahoo!, Bonjour, and many other useful features. It is currently the most feature rich Internet Communicator, and is the only one to provide encrypted audio/video calls, desktop streaming and sharing, and chat on Windows, Mac OS X, and Linux with both the SIP and XMPP protocols.
HTTrack is an easy-to-use offline browser utility. It allows you to download a Web site from the Internet to a local directory, building recursively all directories, getting HTML, images, and other files from the server to your computer. HTTrack arranges the original site's relative link-structure. Simply open a page of the mirrored Web site in your browser, and you can browse the site from link to link, as if you were viewing it online. HTTrack can also update an existing mirrored site, and resume interrupted downloads. WebHTTrack is a Web-based GUI for HTTrack.
Drivel is a GNOME client for working with online journals, also known as weblogs or simply blogs. It retains a simple and elegant design while providing many powerful features, including support for LiveJournal, Blogger, MovableType, Advogato, and Atom journals. (Systems based off these are also supported, including WordPress and Drupal.)
Mrxvt (previously known as materm) is a multi-tab X terminal emulator based on rxvt/aterm. It supports multiple tabs, runtime dynamic tab title, pseudo-transparent backgrounds, user-supplied background images (JPEG, PNG, or XPM), background color tinting, text shadows, NeXT/rxvt/xterm/SGI style scrollbars, XIM, multiple languages (Chinese, Korean, and Japanese) and logging. It is lightweight and fast, and only depends on Xlib.
GMAMEUI is a front-end for MAME on Linux. It helps the user play and configure arcade games more easily. GMAMEUI is an enhancement of GXMame, fixing a number of long-standing bugs, including adding support for SDLMame in preference over the now-obsolete X-MAME. New UI features were also added.