GPS receivers and geocaches Wes brought.
Wes and his father setting up the laptop and projector.
Fiddling with the display.
Jessica brought her ASUS Eee PC small form-factor laptop.
Looking at photos of geocachers geocaching.
Audience shot.
A map of some local geocaches.
... perhaps something near the library? ...
Various GPS receivers.
Another audience shot.
Close-up of some geocache items. Special coins, items with dogtags, etc.
A 3D view of a city, to show how GPS signals can bounce off of sides of
tall buildings, confusing some receivers.