I know this comes up from time to time, so I thought I’d just put it out there for posterity.
Meeting spaces:
3DV is open to having meetings held in their space, and would welcome hosting classes or training. http://www.3dv.com/#/Training/
Multnomah County Libraries have meeting spaces, if they are free, open and of potential interest to the general public. http://www.multcolib.org/services/meetingrooms.html
Event spaces
The Forestry Center
Cinema 21
Hollywood Theater
McMenamins have theater and meeting spaces. I’ve had great success with group sales at the Kennedy School. and massive failure with the Mission. ?
Living Room Theaters
5th Ave Cinema
Northwest Children’s Theater http://nwcts.org/content/event-space-rentals
I’ll post more as I think of them, but please feel free to chime in!