This place is fantastic.
I recently had out-of town company and we went down to NWOC to rent kayaks in Lake Union for the afternoon. They were able to outfit us in all of the gear (without having a reservation), and were really patient in helping those who had never kayaked before. We had a great afternoon kayaking around, includeing paddleing over to Ivars and docking at their docks and having some fish and chips. (one of us stayed and watched the kayaks, of course.)
When we returned the boats, we learned about a guided "sunset tour" that they put on, where you paddle through lake union and through the ballard locks and emerge in puget sound right in time to watch the sunset. They then pack up your boats for you, and give you some kind of shuttle back to your car. We didn't have time to do this, but I thought that it sounded like a really cool idea.
We had a great afternoon, and these guys (and girls!) were so nice and helpfull to us. I highly recommend them!