Putting protection on disk

[CrashMan]

I know this maybe counter productive, but can anyone tell me a way to put a copyprotection on a disk? I have a cd of my own work and I dont want friends to just copy and distribute the cd so I want a way to protect it! I dont care if its just a really simple way that everyone has cracked. Most of the people are morrons and they wont know how to handle it!

Thanks Crash