Ubuntu :: Make A Program The Usuable Thing?

I was curious if you can make a program (lets call it cplay for music). The only thing allowed during a session. I ask this because I wanted to use my laptop as a boom-box for when I have friends over and what not. But I only want them to be able to scroll through Cplay and change the song if they find something else they like. With out them being able to open anything else. I have it so all you can do in the terminal is the Cplay options and you can not end it without ending the Terminal session it self. But now I want only that to be allowed and nothing else. (if you understand what I mean).