HOW?  Give people a pager or phone and ask them to record and evaluate the situation they are in when it rings.

WHY?  This is a useful way to discover how products and services get integrated into people's routines in unanticipated ways.

(e.g.  Developing an implantable defibrillator system the IDEO team distributed pagers to the client team to signal a defibrillating shock. This evoked deep empathy for the patient's every day experience.)