I've been working on a project to show the usual date/time plus Celsius and Fahrenheit temperatures. The software is written in Python and uses several components and libraries from Adafruit, including a 0.56" 7 segment display, a 1.2" 8x8 matrix display, a DS1307 RTC breakout board, and a 10 DOF IMU breakout board. The date is displayed at startup and every several minutes (controlled by a setting), then the time is displayed for 35 - 45 seconds (depending whether the date was displayed or not), and finally, the Celsius and Fahrenheit temperatures are displayed for 7 seconds each. Of course, you can control how long each item is displayed, by changing the settings variables. You don't have to modify the code at all, if all you want to change are display lengths for each item. Everything is controlled using I2C, and the time and date are set at boot up from the DS1307 RTC.
I've also modified some of the Adafruit libraries to give me some features I need, such as rotation and display clearing. I want to expand this project and make it portable, but I need some dedicated processing power. I am roadtesting the ChipKit Pi addon board, but it apparently it's gone bad on me, and really messes up my rPi when I connected it. I don't know who to contact to get this board replaced.
My goal is to convert my project to run on a ChipKit Pi and communicate information back to the rPi over a serial port. Then I will integrate everything into a Device Control System client for the rPi. I've already got a DCS client working on the rPi, so I just need to integrate code from my clock test program into it. Everything is written in Python, so that shouldn't be too difficult. I want the ChipKit Pi to handle all the display and sensor reading, and send the sensor readings back to the rPi.