Algomusic has released MaxScore, a Max object which accepts messages that can create a score, add notes to it, transform them, perform it, save and load the score, as well as export the score to popular formats for professional publishable results.
Description:
MaxScore is more than a notation tool. It is an interactive performance object. MaxScore [...]

Art Institute of Chicago student Chris Burke plays the “Interactopus,” an interactive sculpture controlling sound and live video through eight light sensors, an art bus board, and max/msp/gem.

Gainer is a DIY environment for user interfaces and media installations. It can be used to connect sensors or actuators with Max/MSP.
The basic concepts are:

The user can use it for creative work from prototype stage to final output stage.
Using a breadboard allows the user to learn by mistake.
The user can build their own I/O module [...]