If you wait long enough after a race is done or you wait at the start up screen, a demo of the game will come up. After it is done, goto single race/time trial mode there will be the tracks shown on the demo.
Start a tournament and (you have to get first every time you play) you will unlock secret cars, videos, slideshows, game options etc.
Stop The Clock
At the beginning of any race just as you cross the start/finish line pause the game. If you do this before the clock gets to .10 seconds the clock will stop and not start again. Since in this game you are racing the clock you win the race with very little time on the clock. You will have to do this at the beginning of each race but it is worth it later in the game in the harder races.