FamilySearch, the genealogy research part of the Church of Jesus Christ of Latter Day Saints is a wonderful, free resource for those who are looking for family tree documents. I have used the site and found information not otherwise available, so I have decided to do a bit of volunteer work for them in their upcoming Indexing Project.
I downloaded the software to my desktop, and completed the tutorial, both of which were simple.
The organization is looking for 72,000 volunteers to complete indexing, in English or other languages, for documents in the US or other countries, from July 15-17 (your choice of country and language). You can index as much or as little as you like, but I think it could be addicting once you get started — not just for former librarians like me, but all who love to search and learn from historical documents.