Think you're a history buff? Put yourself to the test with the DocsTeach app for iPad that presents challenges based on documents from the U.S. National Archives. The mobile teaching tool generates activities based on primary source documents such as the U.S. Constitution, a canceled check for the purchase of Alaska and Thomas Edison's patent drawing for the light bulb. Simply pick a historical era or topic and take on the challenge. In addition, teachers can create a free account at DocsTeach.org. This enables them to share a classroom code with students who can take on assigned activities on iPad devices.