We got taken to one by a lovely Thai girl which was hidden on the top floor of a nondescript looking car park. Wicked fun. More ladyboys than you can shake a stick at, Samsong flowing freely and belting karaoke covers of all the Thai classics (whatever they are).
Despite all this, as a bunch of foreigners we were apparently the main attraction- they pulled us tables together in a prime spot, kept offering us drinks and everybody in the place wanted to dance with us. We left about 4am exhausted but grinning.
If you can find it, do it.