It helps, of course, that new Macross comes out every few years, introducing new fans and rekindling interest for the old ones.
Macross World is a fan group with a long and storied history, at least by the standards of such things. I've heard that 2012 is their 30th year, and they've been doing an annual event for the 5 or 6 years. At first it seems that it was an excuse to get together and show off their toy collections, but it's grown as a way to draw new people in as well. Even Mari Iijima comes along, and they do a one-off t-shirt and special toy for the event.
The event itself is held for one day in an art school, in an open mall in the San Gabriel Valley. It's small -- there's a narrow hallway to the main event area, and the dealers occupy spaces carved out of classrooms. Entry is free, but you can buy raffle tickets.
Even though it's small, it's a lot of fun. There's a drawing contest, a cosplay event, a few songs by Mari Iijima, and a speed competition to transform the valkyrie from jet mode to battle mode. (The winner transformed it in 38 seconds.)
I really wish there were more small, specialized events like this. It covers one very specific area of fandom and lets you spend a lazy day immersed in something you really like. It's kind of sad that this is the only part of the anime fandom that does this. It's easy to forget how nice this is when you've been going to a bunch of 10000-attendee events.