I think we need more information if we are to help you. Here are a few questions:
1 First of all, you say it goes back to your command line. You are running it from the X Window System aren't you (sorry if that was obvious but you never know)?
2 Does it give you an error message on the command line after it crashes?
3 What version of Armagetron Advanced is it (at command line type "armagetronad -v")?
4 When it crashes, does it produce a coredump file (this, if it exists, will be in the directory that you were in when you tried to run Armagetron Advanced)?
5 What are the specifications of your computer (especially your graphics card)?
6 Which graphics card driver are you using (default X Window System one or a proprietory one) and have you got the firmware installed, if applicable?
7 Have you got any other 3D games/programs to work on your FreeBSD system?
8 Can you find out what configure options were used for compilation (there is at least one option I know of that will cause Armagetron Advanced to not work)?
If there is any more information that you think would be useful for us to know then include that too.
Note that Armagetron Advanced on my OpenBSD system does crash quite a lot, including at startup sometimes. Try to run the game a few times. Try both "armagetronad -w" for windowed mode and "armagetronad -f" for fullscreen mode.
Off topic: Monkey + Morshu, out of interest could you post a few screenshots of your BSD setups? I've always been intrigued, but I haven't the spare equipment right now to build a system for it, and I detest dual-boot.
Screenshots of my OpenBSD operating system may not be very interesting to you. I have just a plain blue background; no wallpaper, no icons, no widgets, etc. I use the CWM window manager, which is one of the two window managers in the base system. It is very minimal but lovely to use. When I run programs, I run them full screen, so only one program is visible at a time. I can, however, tell you what programs I use. Note that wherever possible, I use programs that are in the base system, rather than in ports/packages. Here is a list of some of the programs I use:
Text editor: vi (not vim).
Screen mulitplexor: tmux (much nicer than GNU screen).
Web browsers: lynx, Firefox.
Graphics: GIMP.
IRC: xchat.