The Skamania County Fairgrounds--which is probably the most beautiful, small fair grounds I've ever seen--occasionally hosts camping for events and group camping. This includes the annual Gorge Gathering of "Tin Can Tourists" on Memorial Day weekend. The four day, three night camp-out features tiny, vintage, and teardrop trailers, bingo, kids games, communal food and meals in the fairground's dining hall, and just a whole lot of fun. Even if you don't want to camp there, you can still come visit during specific "open house" times and see the interiors of many of the trailers for free.
Facilities: One huge, grassy area for all of the trailers that's right on the edge of Rock Cove, a protected and beautiful cove of "small treed islands" off the Columbia River where you can walk, fish, and see bald eagles. Also includes nice flush toilets, an event space with tables, chairs and a kitchen, and a small playground nearby. The fairgrounds are walking distance to the town of Stevenson across a sweet little bridge.
Camping: Other than the Gorge Gathering, it appears on their website that camping may be allowed during the Skamania County Fair & Timber Carnival and as a group campground by application. If you wanted to have, for example, a wedding reception where people could camp out afterward or perhaps a family reunion, this could be a pretty spectacular place.
