Coined from the 80's TV Show of the same name, a "Doogie Howser" is some kid with a genius level IQ. They generally excel in all academics, and are smarter than their peers.
Phil: Hey Steve, it's Friday night! You wanna party?
Steve: No, I need to stay in and peruse my studies. I have that Calculus exam in a week, and I need to prepare myself.
Phil: Okay Doogie Howser...have fun nerding it up!