Portland has a first-rate zoo, your kids will love it. There's also OMSI, the Oregon Museum of Science and Industry. Don't think it's a typical dusty museum, it's full of hands-on demonstrations of scientific principles and very kid-freindly. Growing up in Oregon, my family went almost every year. Even in my cynical punk rock days, I still enjoyed a trip to OMSI.
Your kids will love it.
-Logan
"What do I want? I'm an American. I want more."