An improved user input device is disclosed having ergonomically-configurable features to custom fit individual users. The arms of the gamepad may be extended from the body of the gamepad, and may be rotated. This may be at user determined angles, or may be set to a predetermined limit. The rotation may be on one or more axes depending on the specific implementation. Similarly, the thumb grooves may be extensible and/or rotatable. Further customization may be provided by modular user input systems.