microcontroller

the pic-archive has a good collection of docs, projects and links about http://come.to/thepicarchive
http://www.gnupic.org/
Graphical, PLC-like programming with the PIC16x84 > http://members1.chello.nl/~f.vdburgh/picbit/
http://picnic.sourceforge.net/
LISP-likes
- Taiichi Yuasa > XS LISP on Lego MindStorms.
- Marc Feeley and Danny Dubé → PICBIT, Scheme on a PIC
  - http://www.iro.umontreal.ca/~feeley/papers/ll3.pdf
  - http://www.iro.umontreal.ca/~feeley/papers/sw03.pdf
tutorial on using puredata and pics for data aquistion and analysis > http://www.0x09.com/physcomp/

http://www.arduino.cc/
open-source physical computing platform based on a simple i/o board, and
a development environment for writing Arduino software.
Arduino programming language is an implementation of Wiring(http://wiring.org.co/), itself built on Processing.
The Arduino board is a cheap (roughly 30euros/board, fully assembled), robust i/o board based on the AMTEL ATmega8
http://www.atmel.com/dyn/products/product_card.asp?part_id=2004.
It has
- 13 digital pins (3 of which allow PWM output)
- 6 analog inputs
USB and serial versions boards / pcb schematics available.
Can be interfaced from osx, windows and linux