Python-on-a-Chip (p14p) is a project to develop a reduced Python virtual machine (codenamed PyMite) that runs a significant subset of the Python language on microcontrollers without an OS. The other parts of p14p are the device drivers, high-level libraries and other tools. They’ve released ports for the Microchip PIC/24dcPIC, Teensy 2.0, Arduino Mega and others. Here is their PyCon 2011 Lightning Talk slide presentation.
Some features of PyMite include a memory requirement of roughly 55 KB program memory, supports integers, floats, tuples, lists, dicts, functions, modules, classes, generators, decorators and closures, supports 25 of 29 keywords and 89 of 112 bytecodes from Python 2.6 and is licensed under the GNU GPL ver. 2. However, it lacks a built-in compiler, and does not include any of Python’s libraries. If you know C, Python and how to work with microcontrollers, it might be worth checking out.