Since I am also the FIRST Robotics lead mentor, I plan to incorporate the Robotics Unit within the work for the FIRST Challenge.
In particular, I like the evaluation piece from days 2-3. The students have had difficulty in the past coming up with an effective design that does not require multiple tweaks during competition. Going into next year's competition, I plan to have the students work in several small groups the first two - three days to come up with multiple designs and attempt to evaluate them to see which one (or a composite of multiple designs) would be the most efficient and likely to accomplish the goals of the game.
I plan to extend this into building scale functional models using VEX parts. Hopefully, the design, evaluation piece will go a long way to designing a winning robot.