I think I've flown higher at the Rogue Valley Flyer's airfield in Kerby. Mike said he couldn't see it anymore.
Install "My Tracks" on your Android phone and take it for a ride. Makes an awesome 3D .KML track file in Google Earth showing your flight path.
Just start recording a track, wrap the phone in a big cushion in case of crash. Fly a spiral up and then descend straight down in the center. Makes a neat pattern line in the sky when you tilt Google Earth to see the horizon.
I think I am going to try that on my next flight. I guess I will get a pretty accurate altitude also won't I?