All Alien Characters
Go to the memory card section on the main screen and press left or right.After doing this it should read "codes" press enter and it will say 3extreme. Now you need to erase it by pressing square repeatedly and then by using the directional pad. Alright now you should type in ASTROMEN and you should hear a chime noise then you can play.
Be Geep (97%Bikeracer stats)
Go down to memory card and press right then press X. Earse everything until code screen is clear by hitting square. The type in the word Geep. Then hit X again. Then go up to new season or continue season. Then hit X. Then press right until you see the alien on the screen. Then hit X when you see the alien then on the next screen hit X.