With Different Strokes from Different Folks on hiatus, I was thinking of starting a monthly challenge myself. Fortunately, a lot of "folks" already have. They vary wildly in style, but I thought I'd just start submitting some responses to the challenges.
Studio Atelier, run by Barb Benik, seems to be a familiar fit – everyone painting their interpretation of the same photo, so I've started there. Not many entries yet, but you've still got two weeks.