Teaching interaction design to potentially disinterested students
Engagement
Get them hooked. Find interest for them.
Give them some software, and real life items, that have poor user interaction. Have them use them, and then tell you and the class, what they think of them. What they would to to improve them.
The book The Inmates Are Running the Asylum — Alan Cooper, has some very good real-world and software examples. Including:

Doors with pull handles, and the word PUSH. Can you guess what people do?
Some software bundled with a scanner that had only 3 features, compared with the 1000s in the competitors (want to be adobe) product. It was described as the most feature rich product in its class (it had 3 features, that worked, and were easy to use. That is 3 more than the competitors).

Designing interfaces is boring for a programmer (it is the job of the artists). However “user interaction design” is not. User interaction design goes deeper, it is not about slapping an interface onto a poorly design think. It is about designing it from the ground up to be easy to use.
Computer programming is about two things. The computer, and the humans. Most of the courses are about the computer. However we also learn high-level languages, and how to write programs that are easy to read and maintain (closer to the human). We also need to get closer to the users. By making it easier for them.
Databases
From a database point of view. Imagine a database application with a simple elegant interface, easy to use, but no join. How imagine trying to find some info. Do a query, write the result to to some paper, do another query copying data from paper. However with joins, we don't need to do the remembering for the computer.
Computers should not make us have to remember stuff. Computers are much better at remembering that we are.
Get them screaming at examples of bad stuff from the “Experts”
Which button do you press to cancel? Clue: it is not cancel.


Types of easy: There are two types of easy to use: for the first-times / casual user; for the expert, that uses it regularly. Making it easy for the first-timer, will often make it harder for the expert (often having to work much harder, click, click, click).