Plan B is by far the best of several identities this joint at SE 8th and Main has had over the years. Most recently is was the way-too-hipster Acme (which itself went through a couple of owners and configurations) and before that, it was the blue-collar diner/lounge White Horse.
As Plan B, the interior bar space has been really opened up - big tables, wide-open floor, room for shows, and a good, straight long bar as opposed to the previous, awkward horseshoe arrangement.
The place is fairly deeply punk themed - punk art, skeletons abound, punk and other swagger-heavy forms of music playing (but as with Speakeasy, not blasting). Dollar beers at happy hour (and possibly at other times - not sure). Punk but super-friendly staff.
A notable feature of Plan B is the absolutely massive patio (see the picture slideshow!). It's freaking huge, and for the smokers, has a sizeable covered area (there's mercifully no smoking indoors) for when it's raining. Not like it ever rains in Portland, just saying... ;-)
Lastly, they have a fun menu of decent and cheap food - everything from burgers to balogna sandwiches to much more... unique fare.
I love this place - it is one of my four or five absolutely top places to get after-work relief at.
Keywords: Other North American, Good for breaking up, Just you alone / As a single, Dress casual, Outdoor / Patio seating, Internet (Free), Bar, Restaurant, No smoking, With a group, Happy Hour, Cheap (US$ 5 - US$ 10), Dinner, "In" place / People watching, American, With business partners, As a couple, Very cheap (under US$ 5), Eating late