I’m not technically a native, but I’ve lived an hour from Portland all my life and went there for special trips all the time, which might actually be better than being a native, since they don’t usually do touristy things! There’ve been a few other Portland threads which I recommend checking up on.
My recommendations besides–of course!–Powell’s:
The Chinese Garden
or
The Japanese Garden
(or both, if you love gardens!) The Chinese garden in particular is stunning and should be wonderful in summer time. Tiny and exquisite. The Japanese one is also beautiful at all times of the year.
If you really love gardens, Portland is also famous for the rose garden, which should be nice in August.
Other tourist sites: I spend many happy hours as a kid at OMSI, a very well done science museum. The Portland Art Museumis also nice. Right now, they have a special exhibit on R. Crumb’s illustrations of the Bible, which could be cool if you’re into that kind of thing.
If you like outdoorsy things, the awesome Oregon coast is an hour or so drive away, and Multnomah Fallsare about 1/2 hour drive.
Portland’s also got a really neat Saturday Market. All kinds of good food, shops, and performers.
As for shopping, if you do end up going to Powell’s, there’s a fair amount of cute shops around the area–second hand and vintage clothes, comic book stores, record stores, etc. If you go a little further afield, you’ll get into the heart of the Pearl District–more upmarket and less hip, but lots of cute little boutiques and so on.
Portland is famous for it’s food carts, so if you around during the business day you should check them out. This is a well-known and tasty Thai restaurant. Thisis a bit touristy but I enjoyed the pizza a lot.
As for the Zoo–can’t help you much there, as my family always drives within Portland. There may be a shuttle of some kind? Lots of parking at the Zoo, though.
I also might be in Portland on the 20th, to go to a different concert! (The Hold Steady.) So maybe we’ll pass like ships in the night. 