Someone who blatantly goes out of his way to gainattention to his/herself.
Someone rocking the hell out of a Kiss shirt or some cowboy boots or a fanny-pack could be a rock star mainly because he/she is very nonchalantly drawing attention to his/herself.
Someone singing a Saves the Day song at the top of their lungs in front of about 20 people, not giving a damn what they think, could be construed as rocking out.