Tamarind is a sour fruit, used to add a bitter/sour flavour to Thai curries. The pulp is used to make Tamarind water (also known as Tamarind juice). Some people also eat the flesh of raw tamarind, but it's an acquired taste, and personally I don't like it. My favorite part is the seed kernels. Each fruit contains 4 or 5 of these, but they need some preparation before they can be eaten.
The flavour is similar to a sour nut, but are far harder and crunchier.

Ingredients
Seeds from Tamarind Fruit

Preparation
1. Toast them in a frying pan until the blacken on the outside. You can see this in the photograph below.
2. Soak them in water overnight.
3. Take off the outer layer, and eat the inside kernels. In the photograph above, the kernels are on the right side.