I was surprised to learn from these discussions that certain curries differ only in the amount of chilli powder.

If you take a basic curry sauce (for example Muttley's iin the curry sauce thread, but it could be any that you like - assuming it does not have a great deal of chilli or aromatic spice in it), you can make the following curries by taking as much sauce as you want, adding some garam masala, and adding increasing amounts of chilli to make:

Chicken Curry
Chicken Mardas
Chicken Vindaloo
Chicken Phall

If you wanted to you could use a slightly different masala for each.

You could also add potatos (and perhaps a splash of vinager) to the vindaloo.

In the cheap and cheerful takeaways (and probably a good few resturants as well), they don't have the time or facilites to do anything much else.