Trackyourhappiness.org pings me three times a day to fill out surveys to track my moods, requesting answers within ten minutes to gauge my exuberance quotient.
There's also the MIDI-out port -- if you have a synth handy, you can play a MIDI track -- and as far as plucking is concerned, there are six identical heavy-gauge strings on the body.
Satellites have long been used to track ice extent (area), but calculating the thickness of the marine floes requires the overflying spacecraft to gauge the difference between the top of the ice surface and the top of the water - a relatively simple calculation then gives the overall volume.