In this paper, we introduce a novel context sensitive system design paradigm. Multiple sensors/computational architecture, in the form of our eWatch device, is used to infer the activities that the system is encountering, and can provide a platform for context-aware computing. We created an eWatch prototype that senses user activities and notifies them when important messages have arrived. An accelerometer and microphone provide inputs to a model of interruptibility. A vibration motor for tactile feedback and two ultra bright LEDs for visual feedback provide user notification through different vibration patterns and colors. eWatch is transparently integrated into the user?s environment, and communicates via Bluetooth. This new class of integrated systems underscores the need for new forms of regularity, constraints, and design structure. Our results indicate the power of our method to accurately determine a meaningful context model while only requiring data from our eWatch device.