By the time you get through immigration and take into account taxis to town and back in Bangkok traffic, then getting to the gate 30-60 minutes before the connecting flight you will not have much time to play. Not really much time to party if that is what you are looking for. Go to a local market near the airport and get some cheap Thai gifts for your friends. Sometimes imported Chinese jade carvings are almost a give-away. If you go to Nana I betcha' miss that plane!