Found this gamemode a few days ago and set up a basic server for it, so come join and play some quake, gmod style
join the game from the legacy server browser. Filter the map to q3 or q1 and game to garrysmod
OR find it from within garrysmod under the game mode name "Quake 3 FFA"
the gamemode is only like 50MB and will auto download as you join :>
(server is hosted locally so it may not always be online)