One thing that I always like to do when introducing the Mac to new users is teach them to talk to their Mac. It doesn't matter how young or old the students are, EVERYONE loves this feature.
Step 1 - Open System Preferences
Step 2 - Choose Speech
Step 3 - Select (a) 'Speakable Items' and see (b) a Bubble pop up.
Step 4 - Callibrate your microphone
Step 5 - Say each 'Speakable Item'. Check that the meter stays in the green zone.
Step 6 - Check what key is the 'Listening key' and press that down the whole time whilst you speak clearly towards your Mac. Try asking 'What time is it?'
You should hear a 'whit' sound and your Mac should answer you.
You can teach your Mac to do many things by just asking it. If you want to know what you can ask, click on the bottom of the floating bubble to open the speech commands window.
This is really fun to do. Try it now!!