From wikipedia

reCAPTCHA is a system ... that uses CAPTCHA to help digitize the text of books while protecting websites from bots

I have a lot of scanned documents that I'd like to convert, and would like to introduce a captcha on my website, so why not kill two birds with one stone?

The reCAPTCHA project has it's own agenda though focusing on archives of The New York Times and books from Google Books.

Does a similar project exist that I could host and thereby dictate the books/docs that are digitised?