I was probably 9 or 10 when I started watching
The Mechanical Universe (biased article warning) with my dad. He'd seen it a few times, liked it, and taped it. I'd always wanted to know how things worked, and one time when I asked a particularly tricky question about my bicycle, he pulled out the episode about the fundamental forces of physics and sat through it with me. When he saw that I liked the show he asked if I'd like to watch another (one of the episodes that references Sagan's
Cosmos), and it quickly turned into a weekly event.
I really have to give my father and this series a lot of credit for my academic performance from middle school on up, because it's not a dumbed-down "watch this go boom, it's science!" show, but a real explanation of college-level physics complete with the necessary math (animated math, even). As a result, I already had a grasp of algebra and even some calculus concepts before I ever took a course in them.