The guys (and girls) at Liquidware (of Illuminato Arduino fame) have announced the Illuminato X Machina a small ARM based Arduino like platform that can be interconnected to other X-Machinade to form a cool networked computing cluster.
Each small square board has its own ARM Cortex M3 microcontroller giving each board its own processor, program memory, data memory and I/O. Each board can also interconnected to other Illuminato+X+Machina boards on one or more of its four sides.
This idea of parallelism and closely coupled processor interconnection reminds me of the Transputer from the eighties. The concept of the Transputer lives on in the recently founded (in 2005) Xmos and their multi-threaded multi-core processor with integrated interconnection switches.