Now for something different ... Instructables user 'axpirina' has created an interesting device for a bicycle. By measuring the current speed and determining the deceleration when the bike is coasting to a stop - it will use a laser pointer controlled by a servo to show where the bike will stop if it continues to freely decelerate. The speed data is determined from the pulses generated by a dynamo, and then some mathematics take care of the rest.
Small embedded Arduino projects like the indicator above need an even-smaller Arduino-compatible board - so in your next project, consider the Freetronics LeoStick:
Apart from being one of the smallest Arduino-compatibles on the market with USB, it also has an onboard RGB LED and piezo which can be used a knock sensor and various tune and sound effects. Plus you can add extra circuitry with the matching protostick! For more information and to order, click here.