I actually had one of these and I won't do another one either.

Here's the gist of how it went down:

1) first part was the "personality" interview. Two "HR" people blew smoke up my ass for about 30 minutes about how awesome my site and my work was, then asked me to do a "code challenge". I agreed - I mean, how bad could it be?

2) The code challenge. I was given a PSD with a straight forward design. Asked to code it, make sure it worked in legacy browsers, publish on a server and show them the code on GitHub

3) Passed and then was asked to come back and explain some of my coding decisions. I was told this was more for show and I was already in effect hired, I just had to pass this last hurdle. It turned out to be a very confrontational, inquisition type of an interview. Not at all the type of laid back code review I'm used it.

I got pretty frustrated by the two "Senior" devs who seemed to take great pride in tearing my code and my decisions apart. After my first heated exchange with one of the devs, I actually asked them how many of the sites listed in the gallery on their site they actually tested and validated the code on. They said "All of them, why do you ask?" I told them I actually ran all of their sites through the W3C validation site and none of them passed. Every single one had over 60 errors on it. I basically said, "If standards are so important to you, then why are you holding people who don't even work for your company to a higher standard than those who actually do?"

There was a long silence and then I finally spoke up and said, "Clearly, this company has its priorities in the wrong order. Thank you for time, but I'm not interested." and got up and walked out.

I got several worried calls from the company recruiter, but by then I was so pissed at how much of my time they had wasted, and vowed never to do something like it again.