Ubiquitous computing in it's idealized form brings to mind a vision of calm, yet reactive environments filled with appropriate and timely support for user needs. In practice, this vision is hard to achieve due to many complications including the difficulty of accurately sensing and interpreting user needs, and of building and testing applications. I will present our work in supporting rapid, iterative design of peripheral displays. These displays help to support awareness of information when the user is involved in other activities. They are a crucial piece of Weiser's original vision of calm environments, and thus an important part of creating a positive user experience of Ubiquitous Computing. However, they are difficult to build and evaluate. Our work involves a combination of tool support and explorations of different evaluation techniques.