This paper describes a new software platform for the interactive exploration of human performance models such as Fitts' law. The software is written in Java and provides a flexible environment for HCI research and education. Its distributed, object-oriented architecture provides a framework for exploring new performance models, task types, and selection modes. Keywords Fitts' law, HCI education, human performance modeling, input device evaluation ACM Classification Keywords H.5.2 [INFORMATION INTERFACES AND PRESENTATION]: User Interfaces ? Input devices and strategies.