a six year old solves the subset sum problem: a post on an operations research science fair project.
Roll five dice. Can you make a subset of the numbers appearing on them add up to 10? to 12? Laura McLay's six-year-old daughter did this experiment as a science fair project, solving the problem visually with bars of length 1 inch to 6 inch fitting in a 10-inch or 12-inch frame.
This is both the cutest and most awesome thing I have seen so far this morning. (But be aware that I have only been awake for half an hour.) There should be more things like it.
It's also what I'd do if I were seeing this problem for the first time. (Although, being a Grownup, I'd skip the manipulatives. Which would probably make it less fun.)