Fork 10 children and exec calc in the children. Also, FYI a fork in a loop is called a fork-bomb. Make sure you know exactly how your loop works so that you don't consume all the allowed resources under your OS and kill the box. I've personally seen a 1/4 million dollar machine rebooted more than once over other goofballs doing this. People loose root access, their jobs, or get the FBI called on them for tricks of this sort. =)