weekly challenges?

Hi everyone

Ive been using MyFitnessPal in the shadows for a while now and when Im good Im really good but when Im not bothered I just forget about it.

Ive come back and Im giving it another go, MUST give myself a kick of the bum so I can look good for my wedding in January.

Im seeing a lot of posts about monthly challenges like the 30 squat challenge and the 24hours one but I was wondering if any of you know of any weekly ones? I feel like Id be much more motivated to complete rather than let them dwindle off and forget about them like I normally do!