This lesson can be delivered at any point of a unit provided there is some discussion of a major underdog (ex: ancient Greece, Revolutionary War). The teacher models why the United States was considered an underdog (or another underdog if that is the one you are studying), then students will have the chance to find their own underdog. Towards the end, students can discuss or vote on the underdogs others found.
The old axiom that history is written by the winners has held true in many situations. However, there have been some examples of those who would ordinarily be viewed as losers rising up and becoming winners. Students need to begin looking at those who overcame great odds and achieved success so that they can continue to pursue those types of groups that are struggling against odds, and might not have been able to overcome them.