Carrie C Firman – http://www.carriecfirman.com/synesthesia/index.html
In addition to photography and graphic design work, she also has some interactive works in which you participate in the piece – you can visit the website to get in on the fun! Here is one of her videos, “Synexperience”, and what she says about it.
“Interacting with these two sonar sensors triggers audio and projections of synesthetic sound-to-visual experiences as unexpectedly as they occur to me in daily life. Then, get a friend and try to match the projections!”