I was elk hunting in Central Colorado last fall and I had a bear sneak up on me within 15-20 yards. I had heard some sounds earlier off to my right and thought it could be some elk walking up. So I crowched down to blend in with the grass and bush. I heard sounds behind me too but shook it off as just birds in the bushes.
After 10 or so minutes I heard a twig snap rifht behind me so I slowly turned around. The forest was full of sound so I didn't want to make any sudden movements. After getting my head all the way around, there was a bear standing there just giving me the eye.
Not worrying about making sudden movements anymore, I stood up real quick. After staring at each other for a while, I picked up a rock and tossed it on him and he took off.
I was done hunting for day.