This thesis and supporting portfolio examine the intersections between Irish traditional music, experimental music practices, improvisation and interactive technologies. The author is a traditional musician (harper and concertina player), composer and sound engineer. These practices are reflected in a layered methodology that combines ethnography, composition, historical and musicological research, software and interface design, and performance. A portfolio of compositions, improvisations, experiments and demonstrative videos supports the thesis. The second half of the twentieth century marked a revival in Irish traditional music, as well as a flourishing of experimental music activity. John Cage linked Irish traditional music and experimental music composition in Roaratorio, an Irish Circus on Finnegan's Wake. The thesis discusses the creation and performance of a new, multimedia realisation of Cage's score: Owenvarragh, a Belfast Circus on The Star Factory. It discusses improvisation, unconventional notation, human-computer interaction, chance and indeterminacy in Irish traditional music, and the role of the audience. The thesis further describes new systems for improvisation with and without electronic technology, comparing existing variation with free improvisation from th~ point of view of the traditional musician. The work embraces the presentation of Irish traditional dance music without dancers, and exploits the consequences of this for previously rigid rhythmic structures. _ The idea of the traditional musician as a solo performer shapes the work, and drives the creation of several interactive systems for solo performance of Irish harp with computer. Key issues discussed include the capture of rhythm in live electronics, flexibility in control, and the inclusion of spontaneity in performance. A new piece for harp and live electronics is presented, in which the computer sound is controlled by wireless motion sensor. The intersection of Irish traditional and experimental music is shown to be a productive route to explore a wide range of artistic, social and cultural ideas