This article describes a prototype natural user interface, named the Intangible Musical Instrument, which aims to facilitate access to knowledge of performers that constitutes musical Intangible Cultural Heritage using off-the-shelf motion capturing that is easily accessed by the public at large. This prototype is able to capture, model, and recognize musical gestures (upper body including fingers) as well as to sonify them. The emotional status of the performer affects the sound parameters at the synthesis level. Intangible Musical Instrument is able to support both learning and performing/composing by providing to the user not only intuitive gesture control but also a unique user experience. In addition, the first evaluation of the Intangible Musical Instrument is presented, in which all the functionalities of the system are assessed. Overall, the results with respect to this evaluation were very promising.