I only just saw it on the load screen for the Toy Box and went to see the posting about it on the official site: Racetrack Challenge
Will you be entering? I know there are quite a few of you who have probably already submitted amazing tracks before the challenge went up, which is great! My first Toy Box was not a race (well, there was a minitrack) and I was struggling to decide what to make next and now I've decided to try this challenge.
It says we have one week to submit the challenge.