Ok, now you've asked for it.
Here's a loop I take guests on, which has a little bit of everything...
Head (through some hop fields) to Mt. Angel to see Aalto's library at the abbey on the hill- a nice example of mid-century modernism, as well as form following function design. It's only one of two of his designs to be found in the US, the other is a dorm building at MIT. The Aalto Lounge on Belmont is named after him.
http://www.mountangelabbey.org/library/
If you like German food...
http://www.glockenspielrestaurant.net/
Then head to Silver Falls State Park and do some hiking over, around, and underneath a collection of waterfalls...
http://www.oregonstateparks.org/park_211.php
Then head towards Salem, driving through it, and towards McMinnville to see Howard Hughes' Spruce Goose at the Evergreen Aviation Museum...
http://www.sprucegoose.org/
If you just want to do a quick look without paying, tell them you only want to visit the cafe and/or museum store.
Cap off your day by walking around downtown McMinnville and dining at the rooftop bar/restaurant at McMenamins' Hotel Oregon...
http://www.mcmenamins.com/index.php?loc=7&id=74
It's also wine country around there, so visiting a tasting room could be a substitute for one of the other above activities.