This is so much fun! I'm smiling going through these posts. My 3.5 J was into numbers and letters at 18 months, then books books books. US states, anatomy, what's inside the calculators and pedometers, dominoes, legos, space.. Yes, yes and yes! His room is full of wall maps, gadgets - loves especially the ones that blink crank-up or have levers, an eclipsing moon, revolving solar system and westeren earth that glows city lights. He has more remotes by his bed than I ever have! Lately he's been asking lots of questions about volcanos and tornados, and counting big numbers. He goes back and forth with puzzles, a week on a month off and round again. We explore these things when he can't get to a park or festival... he is happy jumping and walking around goofy, dancing to local bands, and big climbers. Thanks for this thread - fun sharing!