My friend Simon had me use the navigation app on his Android phone one day when we were driving around. BTW he called it a "Droid" but technically it was not one of the "flagship" sort of devices (Motorola specific I think?) which carried the Droid name (most people made the same mistake). While I certainly knew of the general capability of smartphones at that time, experiencing it lead to me joining the smartphone craze just a few days later.
Soon after I got it I was driving east of Fargo with my family and pulled up the Maps app in satellite view. Looking at the nearby imagery we could see that a pond was coming up on the side of the highway soon, and then that pond appeared in real life...man that was soooo cool at the time.
My friend David used to talk about overclocking his Droid X. I think he even broke one by overheating it.