Edgefield is the best of the McMenamin's that are easily accessible from Portland; technically it's in Troutdale, about a 30 minute drive, but it has the biggest campus and most stuff to do. Several small bars and pubs, a pool hall, a distillery, a winery, a golf course, a nice restaurant, and frequently live music or performances... Definitely a fine way to kill a few hours and take in the McMenamin's experience.
If you like doing the walk and shop thing, the Hawthorne neighborhood in the Southeast (mostly between 30th and 39th) and the 23rd neighborhood in the NW (between Burnside and Thurman, although it also extends down to 21st) are good for people-watching and give a good glimpse at the general Portland vibe. Hawthorne is more hippies and hipsters, 23rd is pretty yuppie, but there's a decent cross-section of people in both areas.
Definitely try to stop by a few of the brewpubs. They frequently offer tours and samples, but you'll need to look up the schedules for each one. Off the top of my head, Widmer, Hopworks Urban Brewing, Hair of the Dog, Bridgeport and Lucky Labrador all have local brewpubs that produce beer and offer tours. Rogue and Deschutes have brewpubs here as well, but I don't know if they actually brew beer onsite at those, since they are based out of Newport and Bend respectively.
You could head up to Mt. Tabor. Good biking trails, and it's the only volcano within city limits anywhere in the United States (although it's kind of disappointing as a "moutain"). You could always pee in the reservoir up there and necessitate an entirely unnecessary and costly clean-up...
OMSI is awesome, as other people have mentioned. It's a total nerdgasm. It's geared towards younger people, for sure, but as long as you don't mind some of the "kiddie" feel of some of the exhibits, it's a great place to visit. Not sure what their latest feature attraction is; the last time I went was dinosaurs with a full T-Rex skeleton (a cast obviously, but still awesome to see a complete T-Rex skeleton looming over you).
The Portland Art Museum has a special with classic cars going on right now which looks pretty awesome. Not sure exactly when it ends, but it's soon. If Duesenbergs are your thing, that might be up your alley.