Reader [Joe Saavedra] sent in his latest project: the spatialized umbrella. The base of each umbrella rib features an LED, speaker, and distance sensor. These are connected to an ATMega168 microcontroller running the Arduino environment. The IR sensor triggers a rain drop sound based on proximity. Shorter distances mean more droplets are played. The sounds are generated using a lookup table and the digital pins. You can see the demo video embedded below.
Using the Arduino environment without the associated board is part of another idea that [Joe] is working on. The MapDuino Project uses the standard Arduino hardware for programming, but then transfers the chip to a more barebones circuit in target project. They based their initial work on the ITP breadboard Arduino.