I couldn't stand studying for finals anymore, so I took a break and wrote a debugging skin in MDX for everyone. It does the following:
Momentary on/off for outputs
Analog input display
Analog input logging
The skin logs all analog inputs, in XML format, under the logs directory. Then, to test the logging, I hooked up a temperature sensor, in a glass of warm-hot water. The temperature plot is below.
Partway through, I tossed in some ice cubes, which explains the drop.
And here's what the XML file looks like in excel... super easy to collect data and edit!