BEAM stands for "Biology Electronics Aesthetics Mechanics" and is an approach to simple, biologically-inspired robo-critters, invented by robot engineer Mark Tilden (designer of the WowWee Robosapien).
In a play on Isaac Asimov's famous "Laws of Robotics," Tilden came up with a set of his own laws for BEAM:
1. A robot must protect its existence at all costs.
2. A robot must obtain and maintain access to its own power source.
3. A robot must continually search for better power sources.
Or, stated in more pragmatic terms:
1. Protect thy ass.
2. Feed thy ass.
3. Get thy ass to better real estate.
As these "laws" imply, the BEAM approach emphasizes autonomy, simple, robust design (usually little more than analog components and a solar cell), and improved future designs based on observation of robots interacting with each other and their environment. Mark Tilden is fond of saying that a human is just a way that a robot makes a better robot.
via makeprojects.com