I know this makes my son sound super deprived. But truth is, he has never played with Play-Doh until very recently. What I've done in the past is literally home-make play dough for him out of flour, salt and water; and he was perfectly happy with that. But his eyes lit up when I popped open an actual jar of Play-Doh (these kids know the good stuff). And that one small tub of Doh kept him occupied for more than half and hour in his high-chair.
