The Community Lounge/Cabana areas at TechEd are great. There is a huge room, and around the perimeter, there are areas set up for various technologies. In these areas, folks can informally meet with various experts to ask questions, and have discussions. In addition, small sessions are being presented. This is a great, comfortable way to meet with people and get questions answered.
I am hanging out around Cabana 5 answering questions on SharePoint.