Musical events can enrich application interfaces in two ways: by adding new channels for notifying users about changes in the internal state of an application, or by getting data input from audio equipment connected to the workstation. Such possibilities will only get more widely used if environments are developed in which musical components can be scripted, i.e. can be easily arranged and connected to applications by direct manipulation, as opposed to traditional programming methods. Similar facilities already exist in several systems for working with graphical components like buttons or windows. This paper describes ongoing work for extending one of those systems, namely Interface Builder on the NeXT workstation, with musical capabilities.