This is a thirst-quenching refreshing drink, known as Soda Chanh. My friend, C, tried it and found it quite nice. It is made from soda water, lots of sugar and lime. Seems like it is the expat choice of drink.
A warning to those who are on a healthy diet. Lots of sugar is added into the drink to counter the sourness from the lime.
Recipe:
1 can of soda water
2-3 Tbsp of sugar
1.5 pieces of Vietnamese lime*
Some ice cubes to chill the drink
*Note that Vietnamese lime is different from the local lime we have. It is much bigger in size. Not sure about the taste. Didn't try it personally.