The Squat Challenge is the challenge mandated by my personal trainer. She is doing it with some of her clients. The challenge is fairly simple and has been done before. It was originally done on Live Strong Live Lean (I think) but has been adapted, copied, used, developed, etc. by number of websites/trainers/individuals.
I found the jpg explaining the challenge and have included it below.
UPDATE: My words of wisdom upon completing the challenge.