If you've noticed more food carts in Olympia recently, there's a reason. The Olympia City Council has, as of last summer and due to the urging of a small but persistent vendors, relaxed it's requirements for permits. Before last summer the city required vendors to renew their $180 permits four times a year totaling $470/annually. Now the fee is $180, once a year. This reduced overhead and hassle, along with the allowance of a vendor parking area along State Street between Cherry and Franklin, encourages vendors to set up business and consistently serve their wares.
California tacos is probably the longest standing food truck in the area. They have three trucks stationed in Lacey, downtown and the westside. I've been going to them for years and will vouch for their cleanliness and good quality.
Westside California Tacos
Eastside California Tacos
Downtown California Tacos
Nineveh Assyrian Food - on Plum - check out their fried cauliflower
Another shot of Nineveh and Downtown California Tacos
Filling Station Food Court