Stay squeaky clean-Complete the path of death without dying.
Turn up the heat-Purchase the infernox armor.
Monkeying around-Hit skrunch the monkey.
Be an eight time champ-Complete all of the gauntlet challenges.
Flee Flawlessely-Complete the challenge: The Gauntlet without taking a hit.
Search for sunkin treasure-Destroy 40 under water crates.
Go for a hang time-Get an air of 2 seconds.
Hit the mother load-Get all of the sewer crystils.

p.s:
Sorry about them not being in order or the name of the planet.
p.s.s:
I will be searching for more skill points.