A new Challenge just started in Beta Server - so perhaps we will see it in the Live Worlds next week. It is identical to previous editions - you gain medals to win rewards from any of the 6 different Workshop runs, and any of the 4 types of Spell. I like these! They are a harmless way to add spice to a week without making things over-challenging - and the more of these they have, the fewer Adventures - which I find a bit stressful if they repeat too often. There is no building reward - just Combining Catalysts and Vision Vapors.