Bob Lochel, responding to commenter Jenni who wondered how, when, and where to integrate tasks into a unit:
In my years as math coach, the most efficient piece of advice I would give to teachers is this: think about your favorite problem from a unit, the problem you look forward to, or that problem which is number 158 in the last section which you know will generate all kinds of discussion. Without fail, this problem is often done last, as the summary of all ideas in the unit. Okay, why not do it first? Keep it simmering in the background, flesh it out as ideas are developed and pratice occurs. It often doesn’t take a sledgehammer to make a good unit great.