Here is my idea:
I want to load firmata to an arduino, then use a serial LCD keypad to connect to the arduino, use firmata protocol on the LCD keypad to control the arduino. This should be quite useful. You don't have to carry your computer to the field and all you need is a firmata arduino and an LCD keypad and you can do analog and digital input and output with the arduino to test out things.
But after searching a bit on the firmata.org I couldn't find source code for the computer host. Can someone point to me where they might reside? It's going to be very useful to get started by reading the source code for the computer.