In 2017 and 2018, the Onassis Stegi will organise Open Day events aiming to allow the general public to engage with important music of the 20th century in an informal manner. Performances take place in various public spaces of the OCC as well as the auditorium and the audience is free to wander about, staying to listen for as long as they wish. Children are welcome and so the event becomes a family outing that has none of the intimidating formality or compulsory attention that is usual in a normal concert setting. Apart from music there are also projections, diffusions of electroacoustic works and videos / documentaries.
The 2017 open day is devoted to the New York School.
The 2018 open day was devoted to the 50-year anniversary of May'68.