BZFlag is a 3D, multiplayer, tank battle zone, capture the flag game that pits players against each other in a networked environment. It runs on Windows 95/98/NT/2000, Linux, MacOS 10.x, Irix, Solaris, and others. An OpenGL accelerator is highly recommended, but it is playable with 3D in software.
climm (CLI-based Multi-Messenger) is a portable, small, yet powerful console-based ICQ and XMPP client. It supports password changing, auto-away, creation of new accounts, and other features that makes it a very complete yet simple client. It is able to send and receive messages from the ICQ network, list users that are offline and online (including their online status), search for users by email address, and look up basic (name, UIN, email) information. climm was formerly known as mICQ.
DeskNow WebMessenger is a Jabber/XMPP secure instant messaging server that includes a Web-based IM client. It can be accessed transparently across firewalls, proxies, and NAT, and supports 128-bit SSL encryption. Other features include the support for unlimited virtual domains, a Web-based administration console, and the ability to send broadcast messages and alerts to all users. It is compatible with the most popular Jabber clients, and can run on any OS.