Fun tip: reCAPTCHA is actually two things, the "re" and the "CAPTCHA". In other words, one half is about testing that you're not a human, while the other half is a legitimately unknown word from a source of failed optical character recognition.

You actually don't have to get the latter one anything close to right; and I think you're given the option of at least one typo in the actual CAPTCHA test.

So when a CAPTCHA looks impossible, try doing the possible half and typing in "balls" for the other half. It actually works with pretty reasonable accuracy.