What race is Speed Racer determined to win to avenge his brother's death in the 2008 movie?

In the 2008 movie, Speed Racer is determined to win the Casa Cristo Classic 5000 to honor and avenge his brother Rex's apparent death. The race is a dangerous cross-country rally where Rex was believed to have been killed years earlier.

The Casa Cristo race becomes central to Speed's personal story and to the film's larger plot about corruption in professional racing. Speed joins forces with the mysterious Racer X and Taejo Togokahn, whose evidence could expose Royalton Industries and its race-fixing scheme.

The race is also tied to one of the film's major twists: Rex did not actually die. He staged his death and later operated as the masked Racer X while investigating the corruption threatening the racing world. Thus, the race represents both Speed's grief and his effort to protect his family's racing business.

The title is sometimes shortened to “Casa Cristo 5000,” but “Casa Cristo Classic 5000” is the fuller name used for the event.