Bui Vien is a famous backpacker street. It has lots of bars with loud music, motorbikes and cars that are allowed to drive through, coffee shops, restaurants, vendors selling cheap snacks, shops with T-shirts and souvenirs, convenience stores, hotels with private rooms and dorms for a few bucks a night, and of course cheap beer that you can drink on plastic chairs in the middle of the street watching the whole craziness.
While walking down the street, you will be stopped by lots of young and neatly dressed hosts and hostesses holding bar menus inviting you to sit and order a jug of beer or shisha in their club. Decide for yourself if you like to sip overpriced cocktails while not holding a conversation because the music is too loud. Alternatively, walk around and have some cheap drinks right on the street. When people start dancing later in the evening, you can see where is the vibe you like.
If you want to escape the heat of the street, go to one of the small rooftop bars. The entrance to those is usually through the hotel's elevators. Just look up, and when you spot one, ask people who work around that area how to get to the top.
A good idea is to get lost in secret alleys, find cheaper food, and often higher quality services like spas or bars with alternative music. TNR is a climatic dive bar, and Khu 13 is a famous nightclub where Saigon Boiler room party took place. There are small bars you can get laughing gas balloons filled with nitrous oxide, and bar staff will be happy to show you how to use them. The gay community always hangs out in Thi bar with live music, and later they go to Republic bar just a few steps further. Don't mix it with Republic Club, another party spot around.
Now you know everything to have a safe and unforgettable night!