I was referred from a friend. First, I had an one hour interview with the hiring manager. Then the hiring manager asked me to have a second interview with his director within the next 10 min. The following day, I had another interview with one of the hiring manager's peers. So within 24 hours, I had 3 interviews. The hiring manager asked me to present and demo their solution the following week. I had some materials to get ready but I had to work the whole weekend as I had only few days. The presentation/demo went pretty well. I was going on vacation the following day. They told me that they would definitely contact me after my vacation. Back from vacation...send an email to the hiring manager...no response...quiet. Reached my referral - he heard my presentation/demo went pretty well. He tried to reach the hiring manager, nothing. I was very disappointed. I was at least expecting a 'thanks but no thanks...' - I was very surprised by their unprofessional behavior.