Upside down balloons with no helium needed.Slide a marble into the balloon before blowing it up, then suspend from ceiling with scotch tape, maybe poster tack - play dough stuff. It is a great idea for a party!
Balloon Wall as a photo backdrop. Tape the strings at various heights to create a wall of balloons. Instant backdrop in any color. Guests could have their picture taken in front of the balloon wall by Mary maybe, sort of like a photo booth.