My colleague Jason Ermer has posted his 7th challenge video, shown below. It’s both an experiment and an exercise in probability.
Video responses can be posted to his website, http://www.collaborativemathematics.org. In the words of his website, this is a unique forum for connecting a worldwide community of mathematical problem-solvers, and I think these unorthodox but simply stated problems are a fun way for engaging students with the mathematical curriculum.