Portland Children Museum - Let the kids run around the Portland Childrens Museum and be as loud as they want. Water play land, building center, Bob the Builder digging area, drive an ambulance, and have the children put on a theatre.
Oregon Museum of Science and Industry - For kid's of any age. Enjoy the amazing and interesting exhibits, go in a submarine, watch and Omnimax movie, and run some energy.
Portland Zoo - With a new exhibit opening all the time, enjoy seeing a new creature from a far away land (and some not too far away). Venture to Africa, come see the penguins, and watch the monkeys swing.