You can't tell if a J-K flip-flop is set or reset just by looking at it. This project takes that simple fact and makes a game out of it.
As you can see from the schematic for this project, you use S2, S3, S4 and S5 to set or reset both J-K flip-flops. You can use this circuit as a game for two people.
First turn power ON. Next one player press S2 or S3. The other player press S4 or S5. Then one player press S1. If both players managed to "match", "LED 1" lights. If not, a sound comes out of the speaker.
Be sure to play with this circuit a few times and find out whether the LED lights when both flip-flops are set or reset (or both).
You can also use this circuit to "test" the compatibility of two people. If the LED lights, the two people are compatible; if you hear sound from the speaker, then the people aren't compatible!
Try some variations of this basic circuit - see if you can add a multivibrator, for example.