My side project involves recognition of captchas; it is a pretty tough one-time time investment to create a recognizer, involving machine learning, image manipulation and statistics, but as payment is on a per-captcha basis, the income after that is passive income. I started with this a few years ago, and after two weeks of obsessive-compulsive hacking, my first dollars started flowing in. All in all it now gets me something like $2000 per month.
Nope, they are not spammers, the captchas are not for creating accounts; it has another use. But obviously I cannot go into details about my customers here.
