The Int'l Farmer's Market is a fun place to go walk up and down the aisles, though it does get crowded.
Each ethnicity/cuisine has its own section, from Viet Namese to Indian to Carribean. There's a huge freezer section full of ...well everything you have and have never seen before. If you only go to one "ethnic grocery," let this be it. It's one-stop shopping. If you've never been to one before, give in to your curiosity. Just be prepared for the fact that some labels won't be in English.