At some time in our career we all have to deal with the hanging sign. It is what you can see across the hall that draws your prospects and suspects (and maybe clients/customers) to your booth. They can see you "across the crowded room" without having to know or search for your booth number.
Hanging signs can take a number of shapes and sizes, but most are fabric-over-aluminum framed (otherwise known as Moss-type signs--after the most popular manufacturer) units. They can be hanging banners, pinwheel shaped, cylindrical (round) or square. They can be lit, motorized (so they turn); they can be hung from light trusses or straight from the ceiling. Professional riggers (usually a crew of two in most cities) must be hired to assemble and install hanging signs from aircraft cables using a crane (equipped with a basket) and proper tools.
Be sure that the design is complimentary to the graphic and structural look of your exhibit and is sized (neither too large or too small) for the space it hangs above.
Three rules to remember:
1. Usually only island booths are allowed to have hanging signs above them (20x20 and larger).
2. Typically they are hung at 16, 20 or 24 feet (to the top of the sign).
3. Don't forget to file your approval of the sign with your organizer and place the order for riggers (to install it) with your general contractor.
(thanks to Gary Donatell, Freeman Decorating St Paul, for providing the example show rules to me)