The Fortress Forever in-game main menu.

Options that do not require that you be on a server

Find Servers - This will show all of the Fortress Forever servers up, along with their tick, amount of players, if it's a public or private server, and what map they're playing.
Create Server - This will create a local server for use in LANs.
Options - This allows you to edit things like your microphone and sound volume, your graphics settings, and your username.
Crosshairs/Timers - This will allow you to edit your crosshair and the sounds the game makes when you are using a grenade. See Setup for more information.
Quit - This will allow you to exit the game.

Options that show up only when you're in a server

Resume Game - This will get rid of the menu and put you back in control of your character.
Disconnect - This will disconnect you from the server you are on.
Player List - This shows the names (ingame and Steam Community) of people playing. This menu can let you mute players.