Thanks a lot for the input! Project based learning has always worked best for me too, so I'm considering to run it as a "make x in 5 days" course. Using the Twitter API might be a good idea. Then they'll understand how to communicate with other services, which is critical. But it might be a bit too difficult for a complete beginner?
Perhaps the final 3 days can be project based, and then use the first two to cover some basics.