A nerd, but without the negative connotations that the word "nerd" brings. Someone who is classically nerdy pursues intellectual activities, but is often derided for a lack of social skills. A peabody also engages in the same pursuits, but also has a full complement of personality and likableness to boot.
Fred talked about the LHC for 30 minutes... I had no idea it was so great. He's a real peabody.