Obviously I'm not one of the new fans :-> However, one thing I've seen done at some regional and local conventions is a welcome/mixer event on the first night of the con that forces attendees to interact with people they don't know, either by grouping everyone with the same last digit of their membership number or by matching some other indicator (random colored dots given out at registration, for example) and having them do something silly or perform some short team task together. If it sounds sufficiently interesting/fun, people will attend, especially if nothing is programmed against it and the guests participate. Then you automatically know more people for the rest of the weekend.