Indie.vc's founder field trip to Tuft and Needle was probably the most valuable conference that I have attended. Everybody flew into Phoenix, had dinner Thursday evening, then spent all day Friday at T&N in sessions with the team. The group size of ~20 people was small enough to meet everybody but large enough that you could constantly be meeting new people. The sessions oriented everybody in discussing business tactics. However, the content was a bit dense - there was little time to relax and recharge. If the same amount of content was spread over 3 days, I think it would have been a lot more valuable.