We have on several occasions done an MSE type "project" with K-12 students (usually 2nd grade and up) as a part of our Laboratory Exhibits Day, with pretty good success. For these exhibits, we have approximately 2,000 K-12 students visit the college to participate in various lab exercises, demonstrations, and tests throughout the day. Generally groups of 10-20 students go through the exhibits in roughtly 15 minute increments, visiting different stations. For the MSE station, we basically divide each group up into a handful of teams, then give each team a pile of dry sand and some geosynthetic swatches (could be paper though) and tell them to build the tallest pile of sand they can (adding water is not allowed!). We give them about 10 minutes to try and then show them what can be done if the students are unable to figure it out. We spice it up with a t-shirt for the ones that are successful and perhaps show applications to demonstrate that the approach is actually used.