I find Tim Murray-Browne’s collaborative work with the Music Hackspace, The Cave of Sounds, to be a very compelling example of interactive instruments:
First, the project is an installation (not a performance), so all visitors are invited to participate. Second, there is a range of unique instruments requiring varied types of interactivity, upping the odds that visitors will find at least one piece to connect with. (I think this diversity is what makes the piece truly successful.) Third, the instruments are installed in a circle, encouraging visitors (often complete strangers) to interact with each other, in addition to the instruments.
Also, Mitsuko might find Tim’s Serendiptichord – a wearable instrument for dancers – of interest: