Open a digital watch and take out the watch module including battery and display. Connect a two phase cable to the microphone connector of a tape deck. Then pierce a needle through each phase of the cable at its other end. Press the Record button on the tape recorder and set the counter to zero. Now you can start touching signal lines on the watch module with your two needles. You should be able to hear some pretty interesting oscillations. Write down the counter value when you hear something interresting and sample it afterwards (I tried this as a twelve year old with my first digital watch after the display broke. I was very amazed by the sounds I heard - But unfortunately forgot to record..)
(via The Fix)