Sky Ear is a glowing cloud of 1000 helium balloons attached to mobile phones that can be called while they're in flight so you can listen to the electromagnetic sounds in the sky. The balloons communicate via infrared and create new patterns as they respond to the electric waves (including those caused by the phone calls) in their environment. Sky Ear has been launched twice, and there are not yet any additional launches scheduled.

You can, however, still be a part of Urballoon, by Carlos J G/>=mez de Llarena, which is part of Spectropolis 2004. The balloon will be located at the entrance of City Hall Park on October 1st and is equipped with a projector and a wireless internet connection so people can submit text and images which will be projected directly beneath the balloon. The balloon will begin broadcasting at sunset on Friday, October 1st. The queue for submissions is open now.