I've commented in another message about about holding a booth at AFOLcon somewhere in the future and I'd like to expand on that.
Of course, having an actual booth may prove difficult, depending on the events. Most will gladly give you room to show your creations, but having a booth just to advertise something as bricks.SE may be overcooking it.
But of course, if we happen to have a booth to display some creations, we might as well publicize SE a bit. What's the proper way to do that? "Business cards" seems an obvious first step, but what should we have on them? Are there any official guidelines from the overlords on that matter? I imagine other SE sites do something like that regularly.
Another LEGO-specific idea is to build a QR code with white and black tiles, which work perfectly for people with a smartphone and doesn't take up much display room.
What if we're attending events as guests? I'll go to Fana'Briques this year (as every year), but due to the ever-increasing popularity of the event and overbooking, I won't have a stand of my own (just a few GBC modules, if that); so what can I do there to promote bricks.se?
If we're going to hand out business cards, we might as well try to find a design everybody agrees with.