I think there is a lot... just depends on what part of town you are in. I've played at MHCC, Mt Scott, Montevilla various highschools etc... THe Hoop in Beaverton has open times I am sure...
http://hoop-beaverton.ezleagues.ezfacility.com/default.aspx Check out
Portland Basketball for local leagues... over 190 teams! They also have a noon hoop program... from 11-12 or 12-1 in the Pearl
Noon hoops
Best might be to just join a gym with some nice courts... they will have pickup games some nights. I can't believe how empty some of the gyms are though... it is crazy... I would have killed for all the options when I was young enough to actually play well. =)