Software developer and PS3HaX member zembor0, who was responsible for creating the popular Custom Dynamic Theme software, has created an awesome Hardware mod for the PS3, here is a small quote from his thread:
this is my PS3 case mod, there are 4 seven segment displays on the front. The left two show the temperature of the PS3 from a LM35dt temperature sensor i have added between the two heat-sinks on the motherboard. The two displays on the right show the current fans speed as a percent. The fan speed will go up as the temperature goes up, or you can set the fan speed manually with my TV remote. The display can be turned on or off with the remote, also you can make it count down from 99 to 0 in 1 second (i got bored so i added this, there is not practical reason).
I have also added a blue PlayStation logo on the top of the front of the PS3, as well as some red LEDs shining out of the air vents on the top and the front of the PS3. These LEDs have three modes, ON, OFF, and sound reactive. They will flash to whatever sound is coming out of the PS3. Of course these modes are selected from the remote.
To view the full article, visit the thread here.
If Hardware mods aren’t to your taste, you could always check these PS3 body paint customisations, created by PS3HaX j0nnymofo, check the image below.