Clubs. Portland has more clubs and live music than just about any other city. Lots of folk, jazz, pop, dance, etc. I can’t guarantee you’ll hear good music because my band’s not playing any Portland clubs that weekend.
If your tastes are somewhat refined, I highly recommend having breakfast at the Heathman Hotel (stay there if you can) and catching a performance at the concert hall next door.
Visit the Japanese gardens in the hills of the city for serenity, beauty, and a great view of the city and mountain.
Take a brewery tour - many good ones to chose from. Portland Brewing Co., Bridgeport, Saxor, etc.
If you’re into buying homemade crap in the pouring rain you can visit the Saturday Market on the west side.
The Columbia River Gorge must be seen.
If you’re into skiing or snowboarding, it’s a small drive up to Mt. Hood and the snow is great here.