Piccolissimo is the smallest self-powered flying vehicle (to the best of our knowledge). Thanks to its passive stability, it can fly with only one actuator. This makes it simple and low cost to construct and less likely to have a component fail.
SMORES-EP is a modular robot designed and built at the University of Pennsylvania, and used by researchers at Penn and Cornell. SMORES stands for Self-Assembling MOdular Robot for Extreme Shapeshifting, and EP refers to the Electro-Permanent magnets the modules use to connect.