This is a map that I got through an email chain. It shows the foods that are characteristic of different Indian states and gives you an idea of the diversity of Indian cuisine.
Most Indian restaurants in the U.S. serve Punjabi food (second state in the map from the top-left) -- but there's a lot more to Indian food than that.
The attribution was stripped off, so I don't know who to credit for the map.
Click on the map to see a larger image.
UPDATE: Someone named FaizHaider has claimed on Wikipedia that he is the author of this image. Please credit him, not this post if you use this image elsewhere.