Accomplish the indicated achievement to get the corresponding number of Gamerscore points:

Checkered Flag (5 points): Finish in first place in 10 Single Player Single Races.
Bonustar (5 points): Collect all the stars and the GS token on a single run.
Decathlon (10 points): Win all the goals in 10 different Challenge Levels.
Mister Trigger (10 points): Score 200 frags in Deathmatch play.
Galileo (15 points): Collect all the stars in 50 levels (Challenge or Race mode).
Bling (20 points): Finish 50 levels (Challenge or Race Mode) in the Gold Time or better.
Barrel Roll (20 points): Do a full Barrel Roll and then land safely on the track.
Big Air (20 points): Leave the track and fly for 10 seconds, then land safely on the track.
Indy 50 (20 points): Win 50 Multiplayer races.
GS King (25 points): Find and collect the GS token in every Challenge level in the game.
DeathRay (25 points): In a Deathmatch, use a DeathRay on a player who is using a Flaming Shield.
Temple Master (25 points): Complete the Temple of Doom Challenge Level without a single death/restart.

Additionally, the following achievements are available with the "Turbo Boost Expansion Pack" bonus downloadable content:

Penguin Ace (15 points): Get a perfect score (150) in Penguin Bowling.
Century (20 points): Snaker: Collect 100 stars.
Can't Touch Me (15 points): Win 10 games of Reverse Tag.