If you grew up watching Nickelodeon, then there's a very good chance that you've seen episodes of the popular cartoon Hey Arnold! The animated series premiered in 1996, and the premise revolved around Arnold, a fourth-grader with a football-shaped head, and the different ways he dealt with living in a big city and problems he and his friends encountered on a daily basis. VoxFans of the show will recall that Arnold lived in a boarding house located the fictional city of Hillwood with his grandparents, but one thing that remained a mystery was his parents' whereabouts.Hey ArnoldThe writers of