Aztec Willie & Joey Rose Tacqueria--Cheap Mexican and a glassed-in children's play area make this a good choice for families on a budget.
Dan and Louis Oyster Bar--You'll feel like you're eating in the hold of an old sailing ship, and all the fascinating stuff on the walls will keep the kids entertained.
Old Wives' Tales--This is just about the best place in Portland to eat if you've got small children. There are children's menus at all meals, and in the back of the restaurant there's a playroom that will keep your kids entertained while you enjoy your meal.
The Old Spaghetti Factory--This chain of inexpensive Italian restaurants got its start here in Portland, and the restaurant here just might have the best location of any in the chain--right on the bank of the Willamette River. Kids love the food and parents enjoy the atmosphere and low prices.