Almost all children enjoy coloring and drawing. It's surprising how quiet and concentrated they can become. This is something that not only applies to toddlers, but to kids that are a bit older. Children also learn by doing, so if you tend to spend hours sketching in a pad or designing stuff on your computer, your children will probably want to do the same.
This art table creation is by Jen of Fork, Paper, Scissors and the base is an IKEA Lack coffee table ($39.99). She added chalkboard paint to the top and the rest of the hack involved creating a sort of drafting table mock-up, using an IKEA Mala drawing paper roll ($4.99). A Levolor Universal Drapery Mount ($14.99) served to anchor the roll on one end, and a length of scrap of wood was affixed on the other, allowing an easy way of tearing away freshly created art. The art roll rests on a 7/8-inch dowel rod, but the drapery mount and dowel rod could be replaced by a sturdy towel rod. A bit of overhead lighting wouldn't hurt or you could place a few IKEA Dioder light strips to give the area a nice ambient glow.
You can find more photos and more specifics of Jen's project on Ikea Hackers. All in all, the IKEA table can be replaced by any table with a wooden top. You could probably hack or repurpose an extra coffee table or something that you found at a garage sale or on Craigslist to save a bit of money.