If you've ever wanted to learn how to hack a circuit's firmware, a great beginning point would be SparkFun Electronics. Many of the development, prototyping, and sensor products sold by SparkFun come equipped with a special programming interface. Even better, most of these products feature downloadable firmware. Therefore, with just a modest amount of effort, you can modify one of these products' firmware, reprogram the circuit, and create your own customized product.
You can add your name to a splash screen, develop a new product feature, or -- living life on the edge -- rewrite the whole shebang and make an entirely new product: the sky's the limit when hacking firmware. There is one very important caveat, though: if you don't know what you're doing when tinkering with firmware, you could destroy the product.
In this introduction to firmware hacking, let's try a simple modification. We'll reformat the output from the USB Weather Board v1 so that it can be meaningfully displayed on a serial-enabled 20x4 LCD.