Once, with a group of 7th graders (but I think it'd work with 5th graders as well), I explained programming as a form of puzzle-solving, illustrated by a little

Once, with a group of 7th graders (but I think it'd work with 5th graders as well), I explained programming as a form of puzzle-solving, illustrated by a little game based on an old puzzle/problem: "You have a 3-gallon jug, a 5-gallon jug, and an unlimited supply of water. How do you get exactly 4 gallons of water without estimating?" We made it a game by having them write down the steps they would take, e.g. "Fill five gallon jug, pour from five gallon jug into three gallon jug, etc...", with a prize of a candy bar for a correct solution. I gave the talk to 5-6 groups of ~20-30 7th graders, and there was at least one correct solution in every group. My favorite was afterward, waiting in the library for the end of my wife's workday, one of the kids spotted me and came over to ask questions about alternative approaches.