From the Super Mario Wiki
Mario Raceway, known as Mario Circuit in Japan, is the 2nd shortest course and the fourth and last course in the Flower Cup of Mario Kart 64. The course returns in Mario Kart Wii as the last course of the Shell Cup.
The course features Mario's red cap on the top of the course's terrace, next to the starting line. The road is made of concrete, just like Luigi Raceway and Royal Raceway. Although the course has no pit hazards it's filled in rough grass, and running over them, will cause any kart to slow down. However, using a speed booster as a Mushroom or a Star, drivers can make shortcuts through the grass and dust. Piranha Plants are an obstacle found over the grass, and bumping into one causes the Kart to spin around. Many Piranha Plants are located near to the corners.
Upon getting to the first turn, the racers will go near a hill to take a semi-circular turn surrounding a big toadstool. A long stretch of the road will come next, leading the racers to a curl S bend and pass through a Warp Pipe tunnel. The racers end crossing the finish line once they exit out of the pipe.
Appearance in Mario Kart Wii
Mario Raceway returns in Mario Kart Wii as the last track of the Shell Cup. Some of the new elements added to the track are a ramp to perform tricks in the middle of the rough grass past the toadstool, and Shine Sprites can be seen on the "Mario Star" advertisements on the side of the course near the finish line. In addition, the first Mario Kart Wii tournament of November 2008 is on this racecourse, with extra obstacles such as Pokeys from DS Desert Hills and Dry Dry Ruins, and oil slicks from SNES Mario Circuit 3. Also one part in the music is remixed in Neo Bowser City.
In Mario Kart Wii, a tournament took place on this course. It was a time trial race, in which players used the Golden Mushroom to get the fastest time possible. Oil slicks and Pokeys also made an appearance. The tournament was the second tournament of November 2008. It was later repeated as the second tournament of November 2010, the second tournament of March 2012, and the first tournament of June 2013.
Mario Kart 64
Mario Kart Wii
Names in other languages