import java.io.*;

public class MadLib {

    public static void main (String [] args) throws IOException {
	// Setting up the reading:
	// Create a buffered reader
	BufferedReader in = new BufferedReader(
			new InputStreamReader(System.in));
	// to read a line of input, use in.readLine();
	String input;

	// set up the text:
	String text = new String("There once was a ADJ1 PERSON");
	text = text.concat(" who lived in a ADJ2 OBJECT");
	text = text.concat(".\nThe OBJECT was so ADJ2 that on rainy days");
	text = text.concat(" PERSON had to VERB. The end.");

	System.out.print("Please enter a person or an animal: ");
	input = in.readLine();
	text = text.replaceAll("PERSON",input);
	System.out.print("Please enter an object: ");
	input = in.readLine();
	text = text.replaceAll("OBJECT",input);
	System.out.print("Please enter an adjective: ");
	input = in.readLine();
	text = text.replaceAll("ADJ1",input);
	System.out.print("Please enter another adjective: ");
	input = in.readLine();
	text = text.replaceAll("ADJ2",input);
	System.out.print("Please enter a verb: ");
	input = in.readLine();
	text = text.replaceAll("VERB",input);

	System.out.println("\nHere is the story:\n");
	System.out.println(text);
    }
}

This is an example from CSci 1211 course.