Have you had indian food and noticed (besides all the spices) a tangy, sour flavor?
That, in all probability, is that of the tamarind. The "imli" as is known in Hindi has been widely used in Indian cusine. Surprisingly though it is not native to India, but is from tropical Africa. All ye indian food eaters, can you imagine what sambhar or pani puri would have tasted like if this tree had not made its way here? gosh!
The arabic people seem also to think that tamarinds are from india, as it is called the tamar hind or indian date in the middle east. In north america it is not very well known; the people of the caribbean are acquainted with the tamarind only too well though - i found packets and packets of yummy sugar coated tamarind balls in all the supermarkets in the virgin islands.
Here are the pods, many on the tree and quite a few on the ground below as well: