This paper introduces an audio synthesis library written in C with "object oriented" programming principles in mind. We call it OOPS: Object-Oriented Programming Sound, or, "Oops, it's not quite Object-Oriented Programming in C." The library consists of several UGens (audio components) and a framework to manage these components. The design emphases of the library are efficiency and organizational simplicity, with particular attention to the needs of embedded systems audio development.