CSecurity::ban

Bans the given CPlayer for the given length of time, in minutes.

void banPlayer( CPlayer@ player, s32 time_in_minutes )

Usage example, in which saying '!banme' in the chat will cause the player that said it to be banned for 10 minutes:

void ProcessChat( CRules@ this, string text, CPlayer@ player ) 
{
  if (text == "!banme")
    banPlayer( player, 10 ); // 10 minute ban
}