|UPDATE 8/7/2104:It appears that Google occasionally will randomly and silently drop the authorization for an Apps Script web app. If you notice that your spreadsheet has stopped updating and you know that your logger is still working, then you probably need to log into your spreadsheet from a web browser, go into the scripts editor, and manually execute any function in the script. This will cause a popup that will reauthorize the script and everything will then start working again.
I think this is the last straw. I can not recommend using Google for logging (or any other non-trivial application) any more. This stuff is just too flaky. Sorry.
If you are like me, you often find yourself in a situation where you need to log multiple channels of temperature data. From testing nano-insulating paint to debugging an overheating geothermal well, most of us will have need of accurate and frequent temperature logs at some point in our short and brutish lives.
Here is a recipe to make a reliable, cheap, and easy cloud-based, multi-channel temperature logger using an Arduino Yun and DS18B20 temperature sensors. I chose the Yun because everyone loves Arduinos and this one can connect to the internets. I choose the DS18B20 sensors because they are awesome and cheap and accurate and you can hook up lots of them to a single pair of wires.