In my experience, most of us start blabbering about powerful systems for storage, retrieval and analysis of geographically bound data etc..., but nothing near to the stuff needed to fuel a good conversation. You have to puzzle people, to come up with intriguing questions that grab their attention. I tried to give it a shot: 

- Did you ever stare at the screen of a car navigation system and wondered how the heck that little box knows where it is and how to get you to your destination? - How might a burglar identify areas of high housing prices, high incomes and low levels of dog ownership? 

- Did you ever wonder why they first open up the pavement in front of your house for sewer renovation, followed shortly by new gas pipes, and only months later again for fibre cables, instead of doing it all in one go? 

- Do you know how European crop production quota are monitored, without having inspectors going round 300.000 farms drinking coffee and interviewing the farmers? 

- Do you know why you shouldn't use your mobile phone while plotting a coup or a bank robbery? 

- How on earth can planners and environmentalists combine and evaluate the myriad of natural and human factors that influence the trajectory of new high speed railways or motor-ways?

- How long did you wait before the municipality granted you a building permit for the new extension to your house? 

- The new telephone-directory on CD-ROM includes maps that cover the whole country, on which each marked address can be highlighted. How does it know where everybody lives? 

- Could we estimate the potential number of customers of a new grocery shop, assuming everybody frequents the shop nearest to his or her house? 

If these questions still don't do the job, ask them if they know the word for those little plastic bits at the end of their shoelaces.