We present a framework for assessing which types of simple movement tasks are most discriminative between healthy controls and Parkinson's patients. We collected movement data in a game-like environment, where we used the Microsoft Kinect sensor for tracking the user's joints. We recruited 63 individuals for the study, of whom 30 had been diagnosed with Parkinson's disease. A physician evaluated all participants on movement-related rating scales, e.g., elbow rigidity. The participants also completed the game task, moving their arms through a specific pattern. We present an innovative approach for data acquisition in a game-like environment, and we propose a novel method, sparse ordinal regression, for predicting the severity of motion disorders from the data.