Capture the Flag
Capture the Flag (often abbreviated as CTF) is a team battle gamemode in SuperTuxKart. It is playable online only.
In CTF, players are divided into two teams, red and blue, just like in Soccer. Each team has a base where its flag (of corresponding color) is stored. A team needs to bring the other team's flag to the own base while its own flag is also located there. To take another team's flag, a player needs to touch it. To prevent rivals from carrying the team's flag, players can use powerups to hit a player with flag. This leads to flag loss in that place, and the player that was hit returns to his starting position without any powerups (which can be far away). Then the own flag needs to be touched to be returned to the base.
A player gets one "flag" and 10 points for capturing the flag. A player gets one point for hitting a rival and minus one point - for rescuing, just like in FFA. A player can himself or anyone in the same team without bad consequences.
Typically a game lasts until 10 minutes pass, or until one of teams captures 5 flags. Players' points are not taken into account while determining the winning team (if any), but they can be used to compare players.
You can find a list of CTF arenas here.