The Circuit last night was MUCH more crowded than I've ever seen it on a weekend! A pretty solid line of people watching pretty much every wall. I've never been on a weekday because of my job, so I can't compare. I imagine it's because people who like bouldering tend to like doing things outside on the weekends, unlike me.
Places to hang out in Portland? Coffee shops! Heart, Coava, Ristretto are all very good. Even good ol' Stumptown. The Eastside isn't deserted, it just doesn't have the downtown office crowd during the day. People gather at bars at night, including downtown and near downtown. If you're into it, there's Ground Kontrol just north of downtown---it's a bar/arcade. There are also a handful of movie theaters---some very cheap---that serve beer (Laurelhurst, Cinema 21, Living Room, Bagdad). If you want to go for a walk, the Japanese Garden and the neighboring arboretum are nice (the former has an entry fee).