A 28 pin 8 bit microcontroller in a DIP package as used on the Sumovore Atmel Brainboard add-on.
The ATmega8L is a refined 8 bit microcontroller with 8kb of program memory and 1K of SRAM. Runs at speeds up to 8MHz producing 8 MIPS (about 2000 times faster than a BS2).
Yes, we know it's almost heresy for a BEAM-centric company to sell a microcontroller, but this is one pretty good little unit. Combined with the free open-source tools (see Sumovore Atmel Add-on for download link), it's proven to be a well-appreciated component around Solarbotics, although we still insist on using as appropriate technology, being used where it makes the most sense.