Songs can be used to:
And, for the most part, the song doesn't need to be very long. In fact, the N-B-C song I used as a reminder about assignments needing the proper name, number, and date info is only 3 seconds long.
With that in mind, let me show you a very cool iTunes trick for using just part of a song.
Song Clipping
Open iTunes and click on the song you want to use.
Open the Info Box. (Use a right-click for a PC or a command+I for a Mac. You can also access it in the File menu at the top of the screen by clicking on Get Info.)
Click on the Options tab.
Adjust the start time and/or stop time so that you end up with just the music clip you want.
Be patient as it takes a bit of trial-and-error to get things just right. You can get a rough idea from the progress bar at the top of iTunes as the song is playing.
After that, it's a bit of back-and-forth as you adjust the time length and then listen to the song.
Important: Make sure you use the correct dividers when entering the time. A colon is used to separate minutes from seconds and a period is used to separate seconds from tenths of a second.
Suggestion: Turn off the cross fade effect--found in the iTunes preferences panel--as you're playing around with the time settings. If the cross fade box is checked, you'll hear the beginning of the next song in the playlist as the song you're working on comes to an end.
Here's the song clip I made from the song Me A Me by a Christian group called Rockstar. It's just the first 12.3 seconds of the song.
Note: A song that has been clipped will play that way until the start/stop boxes are unchecked. That means that if, for example, Me A Me is on the playlist I listen to when I'm skating, I'm going to hear the clipped version as opposed to the entire song. But that's okay because the clipping is easy to undo. I just thought you should know so that you're not clipping the songs you listen to a lot.
If you're using Alarm Clock 2 as described on the Classroom Alarm Clock for Mac page, you'll need to do more than clip the song if you're going to use it as the alarm song. For some reason, Alarm Clock 2 will play the entire song even though you've clipped as explained above.
So here's what you do: make a new version of the clipped song in Garageband. As you'll see in the video below, it's easier than you may think.