Amphawa, the floating market west of Bangkok I'm visiting, is famous for its fireflies trip. You'll see fireflies everywhere, on t-shirts, on key-rings as statues of fireflies. It's one of the things you do when you come to Amphawa, and I will be no different, I will hop on a boat head out into the dark river and see the fireflies.
There are a few places to catch a boat along the canal, keep an eye out as you walk. Mine went at 7:40pm and takes about an hour, when you get back that gives you just enough time to eat before the place shuts down for the night around 10pm.
If you want to go shopping, its better to do that before you head out on the trip, as most will pack up at 9pm, you don't really have time to go shopping later.
Fireflies may be famous, but they are not photogenic! Your eyes can see the tiny specs of light flashing away, but the camera? No! It barely catches them.
So this is one of those times you should go and see for yourself. Amphawa floating market offers plenty to do to justify the trip, and Amphawa has home-stay (guest houses) available so you can stay overnight.
The prices are low, 60 to 100 baht each. More if you want a private boat to yourself. You can take the boats for a tour during the day too.