Find the three hidden stars located in Jungle Jamboree GP in single player mode. They are located behind the first jump; after passing the first check point do a 90 degree left turn and go in the square hole that is covered in fire (a short cut), and after going through the short cut go ahead a bit more; and the last one should be visible behind a broken statue head laying on the ground -- you might need to jump in order to get the star.