During gameplay, beat all the levels in Super Career and in every Specialized Career with every rider. Then create 4 tournaments of 12 races each, and beat all 4 custom tournaments with every rider. Now beat all 13 races in Arcade mode with every rider. You should then have more than enough money to buy a $50,000 Protobike. Beat the Incog Time in the Race vs. Incog's Best Time Time Trial in every level with every rider. Doing all of this correctly, and in the correct order will win you a Free $50,000 Protobike with all Upgraded parts, max out all the rider's stats for every rider, and max the stats of all Bikes you have unlocked with each rider. This code also unlocks the Sheep, Deer, and Llama bikes, all the Bike Upgrades, all the Bonus Purchases, and the 3 bonus levels, Free of charge.
Complete any event in career with the listed rider to unlock their pro video if they are an actual pro or a special movie if they are only a character. There video clip will be in the options menu or you can press "Square" when selecting a character.