Doom Legacy has recently (May 2002) been added to the Debian package archive, so it would be the ideal candidate to add, as it should just drop onto the system as it exists right now and run. Doom Legacy is a port of Doom with a lot of cool features, including 'mouselook', jumping, and blood splash effects on walls. OpenGL support in Doom Legacy is the bomb. Eventually, I'd like to add every Doom/Heretic port that runs in Linux.
Here's a small list that I've been thinking about adding to PortaBoom. First priority is to get PrBoom working 100%, then maybe Doom Legacy (see above), then the list below:
atari800 - 8-bit Atari Computer emulator for Linux. This emulator works really well, lets you do lots of crazy stuff with old 8-bit Atari software. [ atari800 section on the reference page ]
xpilot - An Asteroids/Star Trek style game, a Unix staple for years. Good thing about xpilot is that it's multiplayer, and cross-platform as well, so you can play across the internet. [ xpilot section on the reference page ]
Quake - What more do you need to know? Quake was the next generation after Doom in id Software's arsenal. Hopefully by the time a Quake module is written, OpenGL support for PortaBoom will be ready for the world :) [ Quake section on the reference page ]
Yes, game server support is planned both using a GUI interface, and a serial console interface, for running headless. A headless game server can do all kinds of neat and wierd things, like:
Have a server run headless, and with a hard drive, and use SAMBA's web interface from clients to set up shares, then load up the hard drive with files to share.
Have the headless server act as a dialup gateway, using a modem.