I typically have no problem with websites that utilize codes that you have to type to prove that you're a human. That is, until Yahoo! Pool started instituting them. I have nothing against the philosophy, but I've had codes where I've honestly had to try two or three times to enter the right one (you can go back and try the same code again or try entering the new code). I've listed an example below. For the fun of it, I won't reveal what the actual code is until readers have had a chance to guess at it.
EDIT: Here's another one to figure out: