Bangkok is pretty much a 24/7 town still although it is harder to find late night venues now. But if you really want to find it, anything it is there for you. Almost any of all the Tuk Tuk drivers will be most wiling to take anyone to a late night bar/mp/karaoke or whatever you look for. A mp (not wtih a big fish bowl) that usually stay open late is the one in Bangkok Palace hotel which every Taxi driver will know.
