There is a great Hawaiian food cart that is fairly new. It is on NW 10th kitty corner from the back side of Powell's Books. It's a small menu - basically you can get teri chicken or teri beef with the obligatory two scoops rice and mac salad. You can also get either with Yakisoba noodles and veggies.
I grew up in Hawaii and their Teri Beef is really good and authentic. Their chicken is also very tasty. The guys who run it are very nice and very earnest in getting you a great plate of Hawaiian food.
I don't eat veggies so I can't attest to how good the Yakisoba noodles are but I always see at least one or two Powell's employees there which is always a sure sign of a good value - and many of them seem to order the Yakisoba.
Also a new good Happy Hour deal can be had at Green Papaya on SW 12th and Morrison. $2 Pupus from 4 - 6 pm. I'm not a Vietnamese food expert but I enjoyed their chicken satay and you can't beat it for $2. They also have drink specials.
On a side note - I'm still not sold on Mio Gelato and I really really want to like it. But I think it's the texture and the after taste - I can never finish the two scoops even tho the flavor is good.