I did Barbie Bungee when I had my students in Algebra 1. Now, I have them 2 years later in Algebra 2, so it was time for Egg Zipline. We did this back in February, right before vacation. It worked well. It took one 60-minute period. I had students work in groups of 3, I think. In all 3 classes, NONE of the eggs broke. It may have been too cushioned between the shell, the cup, and the cardboard box we were aiming for so I didn't get a mess on the floor. So, next year, I need to adjust it so it is a bit more "dangerous". Typing this quickly. Will find my Twitter friend who started this.