Through "Mash-up" lessons, students can experience events in a new way. It is like the thrill of hearing a country song redone by a pop artist - well, maybe that parallel makes the idea lose steam. Consider ways that you can study an event with a companion piece to invite more complexity and conversation. In a geography class, it might mean that you look at some historical maps. A wonderful resource for this: ArcGIS Historical Maps. Whether working in an economics, history, or geography class, this site provides a range of learning opportunities as your students determine the factors that influenced these changes.
As a way to introduce the challenges facing the United States as it embarked on Reconstruction from the Civil War, I "blinded" the Alexander Stephens "Corner Stone" speech and Jourdon Anderson letter so the sources, dates, and other revealing traits were not provided. Then I gave students a copy of each one and asked them to identify what Reconstruction would need to address knowing that both of these perspectives existed in the United States as the Civil War ended. The goals of newly-freed slaves contrast drastically with the vision of the Confederacy; in addition, students get a sense of enduring issues regarding race relations.
Besides providing two or more perspectives on one issue, another way to execute a "Mash-up" lesson would be to examine a seminal text like George Washington's Farewell Address next to the Tonkin Gulf Resolution, speeches about the Cold War, American actions in Latin America at the end of the nineteenth century, or efforts to create organizations like the League of Nations. Thomas Jefferson's "Tree of Liberty" letter might be a way to speculate on how he would view the actions of Students for a Democratic Society or Black Lives Matter.
Without allowing figures like Washington and Jefferson to become cartoonish, their principles applied to a new context can be valuable. However, a teacher must be careful to keep these kinds of applications corralled so that the historical text is not cheapened, a "Monday Morning Quarterback" attitude does not become prevalent, and presentism (looking at the past only through the lens of modern concepts) does not cloud students' understanding of events in the context of their time.