Each of the following hubs (marked as bold) contains 1 Chicken Challenge except for Midway. Each race track contains 5 race challenges: Race, Fast Lap, Crashinator, Rolling Thunder, Run & Gun. Normal Races and Battles are worth 2 Power Crystals. Every other challenge (except Chicken ones) is worth 1.

(Click a hub or mini-game for screenshots.)

Midway
Mini-Games
Critter Clobber (Duck Shoot)
Von Clutch's Lanes (Bowling)

Mystery Island
Race Tracks
Tiki Turbo
Pirates of The Carburetor
Deep Sea Driving

Battle Arena
Jungle Rumble (PS2/XBox/GC)

Mini-Games
Animal Farm Frenzy (Skeet Shoot)

Happily Ever Faster
Race Tracks
Once Upon a Tire
Track and the Beanstalk
Evilocity

Battle Arena
The Tragic Kingdom (PSP)

Stunt Arena
Hardly Ever Land

Mini-Games
Dropped on Djinn (Falling Target)

Tyrannosaurus Wrecks
Race Tracks
Fossil Fuel Injection
Labrea Car Pits
Tire & Ice

Battle Arena
Extinction Party (PS2/XBox/GC)

Mini-Games
Below The Briny (Protection)

Tomb Town
Race Tracks
Dead Heat
Crash Test Mummies
Pyramid Pass

Battle Arena
Fight Like An Egyptian (PSP)

Mini-Games
Mummy Mash (Falling Target)

Astro Land
Race Tracks
Rings of Uranus
Uranus' Mine
Craters On Uranus

Stunts Arena
Space Stunts

Mini-Games
Astro Lanes (Bowling)
Jellyfish Smack (Protection)