I made this boombox as I like to call it. It is basically a pushbutton, a potentiometer, a buzzer and a 9v battery. It is pretty cool, it fits in my pocket and I take it everywhere. I'll bust it out every now and then to bust out a tune and I can tell you that it's pretty cool. Best yet, they are easy to make and I will teach you how to make it.
Step one: Materials
-9v battery
-12v buzzer (radioshack part no. 273-059)
-Momentary pushbutton
-10k audio potentiometer
-9v battery clip
-wire (any color)
Step 2: Assembly
1. Attach the positive (red) wire of the battery clip to one side of the push button.
2. Attach some wire to the other terminal and the other side of the wire to the potentiometer terminal. There are three side-by-side teminals on the potentiometer you can attach the wires to the terminals on either side.
3. Attach the positive wire of the buzzer to the middle terminal of the potentiometer.
4. Attach the negative (black) wire of the buzzer to the negative wire of the battery clip.
5. Attach the battery and have fun making phat beats with your brand new beatbox!
Hint: This can get annoying. If you aren't making a specific "beat" and just pressing the button over and over and over and over, you might want to make sure no one near you can beat you up. Also, it might not be "airport safe," since 9/11, they haven't been so hot on homemade electronics.
Hint 2: You can add a switch before the pushbutton so that it doesn't accidentally go off in your pocket. The more elaborate, the more coolness points you earn.