Wrote a PHP script that was basically a brain teaser that had nothing to do with Drupal. Then, got called back again to do another brain teaser than also had nothing to do with Drupal. After then, had another code challenge scheduled the next day giving 3.5 hours to do a Migrate module implementation. Never contacted me again after that. Couldn't be bothered to spend 30 seconds to send a "we don't want to hire you" email. I had to stay up all night preparing to do a Migrate implementation in 3.5 hours; obviously that normally takes much more time. Pretty happy I got a job elsewhere.

Difficult, unprofessional interview process where I was essentially doing free work. I would rather be homeless than accept a job with these people. More words needed? Go find a job elsewhere.