Netrek is a multiplayer (up to 16 players) network space battle/conquest
game, with a Star Trek theme.  Players can command one of several ship
types (Federation/Romulan/Klingon/Orion) and can band up in teams.  The
object of the game is, basically, to control the Universe, by capturing
enemy planets, killing the enemy, etc.

WWW: http://www.netrek.org/

NOTE: This is the "BRMH" client.  It is optimized for speed, and so is
well suited to you if you have a slowish system.  However, you don't get
any of the fancy extras, like colors, sound, etc.

NOTE 2: This client is distributed in binary form, because it is a
"Blessed" client, meaning that it has been approved by the "Gods of Netrek"
and has had an RSA key embedded in it.  You can, of course, compile your
own client if you wish, but keep in mind that, if you do so, your client
will be "Un-Blessed" and will probably be kicked out of the official
servers.  This is to prevent some unscrupulous player from hacking his/her
client to give him/her superhuman powers ("cyborgs", or "borgs").