My two most entertaining research projects right now are synthetic insects and smart dust. Thousands or millions of these dust motes will all communicate simultaneously.
Applications are all over the map.
The synthetic insect project is basically smart dust with legs . We're shooting for millimeter scale legged locotion, or possibly flying. Ron Fearing is leading another synthetic insect project in which we're trying to make a micro flying insect . Somewhere in between smart dust and synthetic insects is the micro rocket project , where we're trying to integrate solid fuel rockets into silicon chips.