If you're in for a little craziness (read: sex) and have more money than brains, this is the place for you. First went here thinking it was a bar. Wondered why the waitresses were looking at the gal in our group so oddly...oh, they are not waitresses, they are 'room salon' girls (aka hookers, depending on your expense account limit).
As you may know, R.S. girls often roam the local bars ensnaring wei-gook-in (foreigners) to come to their lair (such as On Y Va) where the real selling takes place. They ply them with drinks and shots, games of pool, noraebang (karaoke, but don't say the Japanese word in Korea) and generally stunning great looks in order to rack up a massive tab. Could cost 2,000,000 won (USD 1,700) for a few hours here with a small group. (Of course the trick here is to set boundaries as to protocol and total bill amount in the beginning, but most can't think that far ahead.)
Dress Code: Since you have the money, you make the dress code. The gals will have skin-tight clothing on, but you're not expected to do the same.
I was actually having a really good time there, until they thought I was drunk and tried to charge an $800 bottle of champagne to me. Filthy thieves... ...so bad.