Wii: Worldwide Mario Kart Wii competition

On May 1st, I got this message from Nintendo:

This is a message from the Mario Kart Channel.

A simultaneous worldwide Mario Kart Wii competition is open from entry.

Get the best time you can in a VS Race on Mario Circuit. There’s something a little different about this race! Can you spot what it is?

Deadline: 10/5 [that's May 10th]