Yot is a project mainly written in ..., it's free.
Yurt of Things
The Yurt of Things (yot) - a simple event system for Arduino boards. See http://www.ddimit.org for more information about the UfT lab.
arduino-sketches/ Sketches (C/C++ code) for the Arudino toolchain. This includes the yot client and some test programs
arduino-libraries/ Custom C/C++ libraries for the Arduino
easy_twitter/ A Twitter library wrapper with OAuth information cached
pyramid/ The Pyramid (formerly Pylons) WSGI server for making events public and general managment
scripts/ Other Python scripts