An integrated sound module makes it possible to record any given sound, or message. The audio content is then activate whenever the motion sensor detects some movement around. As a Non-Visual Graffiti, with its origin in streetart, Soundbombs give the possibility to tag a place in an accoustic form: a welcoming greeting at the entrance or a warning of a bad restaurant.
You can apply to get a Soundbomb and decide how much you're ready to pay for it. However, you'll only be allowed to buy one if Felix decides that your reason for wanting one is good enough. If you're elected, you'll get a unique "accoustic" email addresse (e.g. thud[at]soundbombs[dot]info).
My flickr pics.