@Dawn how about image captchas? :)
Taken from: http://www.sitepoint.com/captcha-problems-alternatives/
Quote:
Tests that use images other than words may be generally easier for users, since all they have to do is comprehend an undistorted picture, rather than decode distorted language. A prominent (and, I believe, pioneering) example of this is KittenAuth:
http://i2.sitepoint.com/graphics/kittenauth.png
The system shows you a set of nine images, three of which are kittens. You have to identify the three kittens in order to pass authentication.

