At a showing of Gran Turismo 5's latest features at the Tokyo Game Show, Polyphony Digital's Kazunori Yamauchi revealed the new special events section of the game, which are slightly different races created for Gran Turismo. There are six special events: Cart racing, an AMG driving school challenge, the TopGear logoed Stigh challenge, a Jeff Gordon NASCAR school, a Sebastien Loeb taught dirt track, and a rally mode.
Yamauchi demoed the special rally mode live for the session. We saw that the stage was automatically generated before his race, and Yamauchi added that this happens every time the mode is selected, and that no two races will be the same. This event features delayed starts and a navigator that calls out corners and routes, just like real rally racing. He pointed out that players will race through multiple stages and will be ranked on cumulative times, and that this mode can be played both online and off.
As you'd expect, Yamauchi was quite good at rally racing in his own game.