@Jeffro - I've been using Mollom on Drupal for years. Its conditional captcha is generally quite simple for a real human. I definitely find it easier to read than reCaptcha text.

Yes, Mollom sends data back to the mothership for filtering. I have no idea what the legal implications are of that in various jurisdictions.

(No affiliation with Mollom or Acquia; just a long-time user of the free plan on my blog. Mollom is the de-facto standard for a large part of the Drupal world.)