Ever had to explain what GIS is to a person that had no idea what it was? Check out this article and you will find some nice answers you can use in the future!
SoCalGIS.org
Southern California Government GIS User Group – Working together locally in GIS
SoCalGIS.org 
This is a good one.
After I say I’m a GIS Analyst, I’ll follow it up with, “I make data pretty and into maps.” Usually that description is followed up with the question, “Oh, so like Google Maps?”