One thing my students struggled with ALL year was working together...we still didn't quite have it down by the time we did this project, but I think the kids that could handle it did great, and so that made it worth it! Each team was given a set of legos (random) in four colors. They had 15 minutes to create a structure. They could make their own pieces and connect them (they HAD to be connected by the end of the time), or they could just build one big one together (harder than it sounds with these little guys...hehe).
After the 15 minutes was up, they switched tables. They had to deconstruct the structure, sort out the colors, and create fractions using the four colors. They got extra "points" for putting the fractions in order from smallest to largest and using the <, >, or = symbols.
I was inspired to do this by a news piece I saw where a middle school teacher used Legos with her sixth grade language arts class to talk about plot, conflict, etc.