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.
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.