I love this idea by Raphael Pluvinage & Marianne Cauvard. Noisy jelly is a noisy chemistry lab, where the gamer creates jelly with water and agar agar powder. They add colour, then let it set, then by touching the shape, the gamer can activate different sounds. More info on designboom, where I found this!
NOISY JELLY from Raphaël Pluvinage on Vimeo.