Something different
Pebble Creek is a cool little campground that because of it's location in Yellowstone National Park, it offers a much different experience compared to most of the other campgrounds in the park, ie, it's more like just being in the mountains, and it's also off the beaten (heavily beaten) tourist path.
There are bears in the area though, so be careful, especially in tents (sometimes they won't even allow tent camping here)
Month of VisitJune