How about using parse.com's new javascript database layer to abstract the requisite server-side dependencies. (disclaimer, I've never used it myself). Then you'll be able to teach a user how to setup a simple one page web app, maybe a todo list, that used jquery's xhr requests to set and get data from the database.
Alternatively you can do this entirely with localStorage, problem there is that you need to provide an extra lesson about why localStorage doesn't work "online" (across the network).
I definitely think javascript is at a state where it's actually easier to understand the underlying principles of programming, i.e. why design decisions are made and how each component is integrated with the next component. Contrast this with rails where everything is magic, and I would much rather learn from a bottom-up kind of approach. When the front-end logic is all taken care of, Your next lesson will be to build "the part that parse.com is taking care of". So you throw up a sinatra app maybe, provide 2 REST endpoints etc. Thinking about applications as a composition of integrated services (database, database api, UI, application logic, etc) proves a lot more understandable and also has the benefit that it's a very mature way to look at things actually!
Just writing this get's me excited to start teaching my friends again. The problem is it's very hard and very exhausting (in a good way but I only have so many hours in the day!)
The biggest problem for me keeping the iceberg manageable. I should let them know just how many TONS of stuff they will eventually need to know, but ideally I want to do that in a procedural fashion so that it makes elegant sense.