I came across a clip from Conan this morning in which he visits a Korean Spa. It's quite similar to the spa Jason and I visited in Seoul, right down to the shiny pink tables for scrubbing; although, there was no clay-bead room in our version (alas!). He is a little crass at some points, but I think it does a decent job of capturing the experience for you less intrepid travelers.
However, I do feel compelled to point out that he not only went to a spa in California (i.e. where the workers speak English), but he brought a Korean-speaker along with him. Somehow I think you haven't truly experienced international bathing until you are completely 100% starkers and have absolutely no idea where you are supposed to go because the wee old Korean lady keeps pointing to the staircase and all of the signs are foreign.