Hi, Austin!
That drive to know can be exhausting, can't it? He sounds so much fun--and lots of work!
When Harpo was that age, we went out every day that it wasn't pouring rain. I threw some field guides in a backpack, and we went to the forest or the beach or a not-too-manicured park, and just identified things--rocks, shells, trees, birds, flowers, little critters (we had one insect field guide which I still have memorized, in order, because I had to read it so many times! and then he'd recite it back to me, over and over and over....). Other expeditions he liked were to demolition or construction sites--there was a lot of that going on here that year, as I recall.
If you have a piano or something similar, you could show him the names of the notes as you play them; all my three enjoyed that as toddlers (and Chico could always tell you the names with his back turned--I wish I could do that!)
All my kids enjoyed our homemade "comic" books--I am the world's lamest artist (but it's all about letting go of our perfectionism, said she wryly)--but I used to staple together a few pages and draw some scenes from our days--Daddy coming home from work, the postman coming, a walk to the park, etc., and write a few words on each page. These were big favourites.
We went to a building supply store and got some really big cardboard boxes (like appliance size), and built playhouses in the living room. We used old remnants to make curtains, and glued buttons on the doors, then the kids would cut up old seed catalogues and gardening magazines to plant the "garden" in the front of the house.
Alphabet scrapbooks were fun, too. Write one letter on each page, then go through your old magazines and cut out pictures for each letter. This will result in some more interesting examples than one often finds in published alphabet books! B is for Beatles, I is for icon, R is for reamer...and G always seemed to be for golf...
We also made rhythm band instruments out of the recycling (take two liquid laundry soap caps, for instance, fill them with beans, and duct tape them together--a nice shaker; or make your classic shoebox guitar with rubber bands, while an empty yoghurt tub with lid is a good drum). Tap out lots of different rhythms together. Harpo loved doing rhythm work at the table: he'd pat out a rhythm with his spoon on his plate, and then Frenchie or I would have to tap it back--that was always a good game.
Another good game, especially in the car, was generating rhymes. Sometimes the strings of rhyming words got pretty long!
I tried to involve all three kids with the cooking quite young, too (obviously not with anything hot or sharp). But they all loved (and still do) measuring and stirring and sifting, and especially smelling the herbs and spices--you could just go through your spice cupboard one day and give him a sniff of everything and tell him the names.
We also used to make our own puzzles, sometimes--I glued magazine pages on an old cereal box panel, and cut them into a few pieces--they're not as good as jigsaws, but might be a lifesaver on a day when he's tired of all the old ones.
Hope a couple of those ideas might be fun for you--
peace
minnie
