National Archives and Records Administration has a nifty program that allows "citizen archivists" to transcribe historical documents in their collection. These records have been scanned, but because they are handwritten or typed, it is not possible to search them. That's where you can help - you can become a citizen archivist and contribute to this important and interesting work. Here's the link: https://www.archives.gov/citizen-archivist.
Warning - this site can be addicting!