Sensemaking is a deliberate effort to understand events or information, and a sketch is an exploratory graphic composition of a concept or observation. Within the architecture domain, sketching is employed during predesign phases to create a shared understanding among clients and stakeholders. While sensemaking is highly collaborative, sketching is usually a solitary activity. This paper describes the design and evaluation of two prototype socialtechnical tools to support collaborative "same time, same place" sketching and sensemaking: (1) a software environment (SketchBook) that allows users to quickly generate and capture ideas; and (2) a wireless, scalable, multi-user pen interface (FireFly). When used together, these tools support simultaneous sketching, diagramming, and annotation within the same work space without traditional bottlenecks of "turn taking" by passing a single pen. This paper presents the motivation for sensemaking and sketching, and findings fro...