There are two different ways of running unsigned code on a game console. One is through soft modding (modifying software, normally using a softmod) to allow the user to change data contained on its hard drive in the case of the Xbox. Another type of modding, known as hard modding, exploits the BIOS of the console to run unsigned code, or games. This form of 'modding' (more correctly termed as hacking) is very popular as it is able to 'run' many different types of software. But soft modding is even more popular because of its ease of installation and its relatively low price (it can even be done for free with the right tools).
Another type of console modding is about appearances, much like computer case modification. Which includes, adding lights (most likely LEDS, cathodes or other electro-luminescent lighting). Cutting the game system case, to fit hardware and/or expose the internal systems. Cooling is a large part of console hard 'modding', including: heat sink upgrades, more powerful or quieter fans, some even go so far as to abandon common heat exchange to air all together by liquid a console (most notably in the Xbox 360, which initially had some heat problems). Hope you guys Liked