I ran into a famous cartoonist in the late 90's and wanted to get his autograph. Unfortunately I didn't have any paper and a pen available at the moment. All I had was my Palm Pilot, so I pulled up the drawing app and handed it and the stylus to him. He signed it and drew a little cartoon as well without a second thought.
Unfortunately there was no good way to get those images off the Palm Pilot so I don't have it any more.