Where they are
Challenges sit in the Play tab, and sponsored challenges show first on the Hub.
A challenge books a crew against another crew at a set time. The game counts the same as any other game: stats, XP and ranks.

Challenges sit in the Play tab, and sponsored challenges show first on the Hub.
Basketball challenges are 3v3 only. Pickleball, volleyball and mini soccer also take challenges. Baseball does not.
A booked 5v5 never takes a court the queue needs, so challenges and open play never block each other.