When a new client signs up to a set program, we can introduce them to challenges on a "level up" basis. At level 1 it could be to complete simple nutrition tasks such as eat more protein, complete 2 workouts per week, be able to run 2km etc. Once they complete level one, they could then go onto level 2 "difficulty" and so on. I think it would be a great lead magnet and easy wins for new clients signing up to a program. Also it could be set for when someone signs up rather than a set date challenge like there currently is