Don't just sit there! Build something!! 
Notes:
It has been my experience that students require much practice with circuit analysis to become proficient. To this end, instructors usually provide their students with lots of practice problems to work through, and provide answers for students to check their work against. While this approach makes students proficient in circuit theory, it fails to fully educate them.
Students don't just need mathematical practice. They also need real, handson practice building circuits and using test equipment. So, I suggest the following alternative approach: students should build their own "practice problems" with real components, and try to predict the various logic states. This way, the relay theory "comes alive," and students gain practical proficiency they wouldn't gain merely by solving Boolean equations or simplifying Karnaugh maps.
Another reason for following this method of practice is to teach students scientific method: the process of testing a hypothesis (in this case, logic state predictions) by performing a real experiment. Students will also develop real troubleshooting skills as they occasionally make circuit construction errors.
Spend a few moments of time with your class to review some of the "rules" for building circuits before they begin. Discuss these issues with your students in the same Socratic manner you would normally discuss the worksheet questions, rather than simply telling them what they should and should not do. I never cease to be amazed at how poorly students grasp instructions when presented in a typical lecture (instructor monologue) format!
A note to those instructors who may complain about the "wasted" time required to have students build real circuits instead of just mathematically analyzing theoretical circuits:
What is the purpose of students taking your course?
If your students will be working with real circuits, then they should learn on real circuits whenever possible. If your goal is to educate theoretical physicists, then stick with abstract analysis, by all means! But most of us plan for our students to do something in the real world with the education we give them. The "wasted" time spent building real circuits will pay huge dividends when it comes time for them to apply their knowledge to practical problems.
Furthermore, having students build their own practice problems teaches them how to perform primary research, thus empowering them to continue their electrical/electronics education autonomously.
In most sciences, realistic experiments are much more difficult and expensive to set up than electrical circuits. Nuclear physics, biology, geology, and chemistry professors would just love to be able to have their students apply advanced mathematics to real experiments posing no safety hazard and costing less than a textbook. They can't, but you can. Exploit the convenience inherent to your science, and get those students of yours practicing their math on lots of real circuits!
Notes:
If your students do not know what a ßolenoid" is, this question is an excellent opportunity to find out!

Notes:
There is a sequence of events to the final result of the pushbutton's actuation. Be sure to ask you students to explain all the steps, from beginning to end, of this relay circuit's operation. Test their comprehension of this circuit, to ensure they fully understand what is taking place.
A logical question your students may ask is, "What is the point?" After all, a circuit with no relay at all (just a switch, battery, and lamp) could accomplish the same task! What is the point of having an extra battery and this device called a relay? Resist the temptation to tell them why, and let them figure out some possible reasons for using a relay.

Notes:
There is a sequence of events to the final result of the pushbutton's actuation. Be sure to ask you students to explain all the steps, from beginning to end, of this relay circuit's operation. Test their comprehension of this circuit, to ensure they fully understand what is taking place.
A logical question your students may ask is, "What is the point?" After all, a circuit with no relay at all (just a switch, battery, and lamp) could accomplish the same task! What is the point of having an extra battery and this device called a relay? Resist the temptation to tell them why, and let them figure out some possible reasons for using a relay.


Notes:
The immediate and obvious conclusion is that four out of the five switches will be nonfunctional. However, it isn't this consequence in itself that is the greatest problem. Rather, it is the silence of the failure  no one knows anything has failed, until they try to use one of the nonfunctional switches! Ask your students to explain what the essential nature of the problem is: what is it about this circuit's operation that makes an öpen" failure in the field wiring so dangerously inconspicuous?


Notes:
Ask your students what essential task the relay performs in this system. Is there any way to build this circuit to have the same functionality without using a relay?

Notes:
If any students ask what "SPDT" means, refer them to a text or other information source on switch contacts in general (SPST, SPDT, DPST, DPDT, etc.).
Ground symbols were used intentionally in this question, to eliminate clutter from the diagram, and also to make students more familiar with their use as a notation for a common (reference) point in a circuit.
This question also reveals another useful feature of relays, and that is logic inversion. The green light operates in the same mode as the pushbutton switch, but the red light is opposite of the pushbutton switch. With just a single pushbutton operator, two complementary functions may be performed through the use of a SPDT relay.



Notes:
Ïce cube" style relays are very common in industry, and it is important that students understand how to interpret the pin diagrams on the cases in order to use them in new circuits and to troubleshoot relay circuits that are already built.
Notes:
Do not be surprised if many of your students neglect to calculate the resistor's necessary power dissipation rating for the resistor, simply because this value was not requested in the question. However, it is important for students to be actively thinking about every problem they encounter, and to try to take all relevant factors into consideration!
In real life, the power dissipation rating of such a resistor would be very important. Failing to account for this value could result in component (and system) failure.
Notes:
The real challenge of this question, of course, is for the students to determine what in the world "pullin" and "dropout" current values are. Once these definitions have been found, it is a very simple matter to experimentally determine them for any given relay.
Notes:
The purpose of this question is to get students to kinesthetically interact with the subject matter. It may seem silly to have students engage in a ßhow and tell" exercise, but I have found that activities such as this greatly help some students. For those learners who are kinesthetic in nature, it is a great help to actually touch real components while they're learning about their function. Of course, this question also provides an excellent opportunity for them to practice interpreting component markings, use a multimeter, access datasheets, etc.