The Box of Sounds was built over 25 years ago by a then 12-year-old Russ. Function wise this device is basically perfect as a stand alone experimental noise maker and an Audio generator. You have Volume, Built-In speaker, oscillator pitch,  LFO with Rate control, and an indicator, old style frequency range selectors, switch patching, and an On-Off switch. All for what appears to be $15 in parts plus a sound generator IC. Circuit wiring is nothing more than a direct implementation of the SN94281 Datasheet schematic, but the user interface and its functional simplicity is something note because it can applied to other basic oscillator circuits.

Here is a video demo.

[youtube]http://www.youtube.com/watch?v=m8h8_kVl7qo&feature=player_embedded[/youtube]

Seen on Make:Blog