Don B.
Yelp
This is a totally awesome event venue. It's beautifully designed, sustainably minded (renovated using repurposed timbers, low-water-use fixtures, etc), has an excellent flow, and it's really simply a pleasure to party in. I've been in this space quite a few times, and while I've never thrown an event here, I've seen other events in action and finally, last night, attended an event as a guest. So this review is really from the perspective of an attendee, not someone who has actually done business with Leftbank.
The main floor upstairs is huge and open and much, much larger than the overall capacity allows. It's really a blank canvas. The main space is airy with high ceilings and a mezzanine area for VIP's or whatever. There's a room for coat check, modular bars, and an in-house sound system. Add in 4 flat screens up on the edge of the mezzanine facing outward that you can use for videos, Wii, or anything else fun like that.
Downstairs offers up a low-ceiling room system that can be segmented into multiple meeting/display/classrooms with a larger open area and bathrooms (that serve both downstairs and upstairs. The downstairs area also has a long loading dock that would be a perfect place to keep your line (should you have one) in a space that's under cover but still cut off from the main space.
Parking is usually available nearby in the Rose Garden East/West lots and there is a small parking area out back for the event organizers and staff.
I wouldn't hesitate to recommend this space for someone who needs a classy venue for an event.