Another in-class activity we present we call "build challenges".  This utilizes Free Build bricks to achieve basic or complex goals, such as a tall tower or building a sturdy bridge.  These are much more free-form activities that let students work with Free Build and design as they wish, while still exploring the engineering aspects using trial and error in designing a solution for the challenge.

Challenge difficulty is scaled based on the building skill observed in class, the age group of our session, and the interest demonstrated by students.  Other example challenges may include balancing a functioning zip-liner, constructing functioning siege machinery or designing the fastest race car.

The left image is of a sturdy tall tower, tested by buffering strong winds against it at the middle and top.  It didn't even move!