A small program that goes to sleep right away and when you wake it, goes right back to sleep.

stop.c

#include <signal.h>

void stop_self()
{
	raise(SIGSTOP);
}

int main()
{
	struct sigaction act;
	act.sa_handler = stop_self;
	sigaction(SIGCONT, &act, 0);

	stop_self();
	return 0;
}