You really can't go wrong with Indian food. Generally, northern Indian is less hot than southern (even Indians from nothern India say they can't eat south Indian food), and it's also more saucy. Try a Murgh Saag (chicken in spinach sauce), or something similar. Get some Naan (bread) and rice, the Naan is much more interesting, but the rice is good to have if it gets too spicy (don't drink, eat some rice to get rid of the pain in your mouth
). And tell them not to tone it down too much, get some middle-to-high spicyness. Just stay away from the green curry for the beginning. And I second the Mango Lassi. I'm sure you'll love Indian.
Great, now I'm hungry ...