In this paper, we introduce MITes, a flexible kit of wireless sensing devices for pervasive computing research in natural settings. The sensors have been optimized for ease of use, ease of installation, affordability, and robustness to environmental conditions in complex spaces such as homes. The kit includes six environmental sensors: movement, movement tuned for object-usage-detection, light, temperature, proximity, and current sensing in electric appliances. The kit also includes five wearable sensors: onbody acceleration, heart rate, ultra-violet radiation exposure, RFID reader wristband, and location beacons. The sensors can be used simultaneously with a single receiver in the same environment. This paper describes our design goals and results of the evaluation of some of the sensors and their performance characteristics. Also described is how the kit is being used for acquisition of data in non-laboratory settings where real-time multi-modal sensor information is acquired simultaneously from several sensors worn on the body and up to several hundred sensors distributed in an environment.