A note of warning: the CTF as a concept does not appear to be as popular currently as it used to be,
Further, our currently running modes allow for FFA like joining any time and allow for quite low player counts to start the game (2 players already) where the CTF mode could impose a limit to this to be any fun.
Further, Team Fortress 2 has an quite lookalike mode called push cart - one team is attacker and must remain in a certain zone around a cart. If no team members are near by, the cart won't go forward. Primary objective is to have the cart reach a certain point on the map.
Quite a fast paced mode.