Last published challenges
Zigzag Boardwalk : Go through all 10 rings in order in Time Trial mode, in less than 45s

Coins in Mario Circuit
Mario Course 1 : Collect all coins in Time Trial mode, in less than 1:25

Do you see a Waterfall? No? Then why are you waiting 3 minutes HERE?
Fourside : Survive more than 3:00

*ring ring* Hello, it's your dad. You've been out there for a while now. Don't you think it would be a good idea if you took a break?
Fourside : Survive more than 2:00

You encountered the Annoying Reveler.
Fourside : Eliminate 1 opponent by yourself

SMAAAAAASH!
Fourside : Hit 4 opponents

Finding Everdread...or rather, Everdead
Fourside : Collect all coins

Gettin' yo girl back
Fourside : Finish the game in the 1st position

Falling in the Water
Fourside : Finish the game in less than 5s

Drinking some "Protein Drinks"
Fourside : Go to Jackie's Cafe.

...So where exactly do you fight in Smash?
Fourside : Go to every intersection.

I couldn't find an image of the Hint Man on WikiBound, so I used the next best thing.
Fourside : Go see the Hint Mr. Saturn.

Rocky Hills Run
EKDS Rocky Hills : Complete the track in less than 1:50 in Time Trial mode

is this my first battle challenge?
Survive more than 3:00 with 1 balloon or more, without drifting, without touching item boxes, without using any item

Sherbet Land : Complete the track in less than 1:40 in Time Trial mode

Équerre
GCN - Piranha Pipe Slide : Complete the track without touching any chèques

Encuéntrame...
Dragon Boy's Rest Valley : Encuentra mi cuerpo corrompido tras quedar atrapado en este videojuego... with King Boo

Sherbet Land : Collect all coins in Time Trial mode, without touching any Freezies, with Rosalina, in less than 1:00

Coin Grubber
Thwomp Circuit : Collect all coins in less than 30s
With 8 participants

why do we exist?
baguette : Complete the track in less than 1:10 in Time Trial mode, without using any item
