I cobbled together an Uno based data logger that can be jumper-ed together very quickly with a few parts and a breadboard. I originally posted about it in the sensors forum, but realized that I probably missed the mark there when I came across this forum, so I'm reposting the link, with apologies for the duplication:
It runs with Tom Igoes wonderful example code from http://www.arduino.cc/en/Tutorial/Datalogger if you change the cable select line to 10.
I added DS3231 RTC alarms & sleeping so that the students can graduate to stand alone builds later. We used this logger to introduce all the basic programming concepts with tethered operation before we started soldering and I am so glad we did. By the end all of them understood programming concepts like libraries, etc, but I'd say only about half of them could solder properly. I really was not expecting the physical part of the process to be so challenging for them.