When I built a new rig (which at the time was my Athlon X2 4200+ w/MSI K8N Neo 4 Platinum), I decided it would be cool to literally overclock my old rig to death.
Looking back I wish I had recorded it because it was pretty cool.
It was an Athlon XP-Barton (2400+?) that I had stable @ 2.5GHz (11x230 IIRC). I busted out my old vantec tornado and popped on the Thermalright XP90c and pulled the side off the case. I just kept bumping up the voltage, multiplier and bus speeds and ran prime 95 until it just couldn't take anymore. I ended up reaching some ridiculous numbers on that chip and it would shut off a few times before it would completely fry at which point I would just give it some more. I really wanted to see if I could hit 100c on speedfan, but only made it to about 96c (or so) before it died. In excitement, I went to pull of the the chip and my heatsink burned my fingertips and left tiny indentations around the fan housing. The thermal grease was baked, but once I cleaned it off my CPU looked pretty normal other than slight discoloration which was disappointing.
It turns out that I was running that rig alot more modestly than what it was actually capable of (yeah I was kinda an OC pussy). I still have the ram that I used which was cheap PC3700 infineon with copper heat spreaders that would take anything you could throw at it. It's in use right now in a CentOS server test rig...
The Mobo was a Shuttle A35n and I pulled the cooler off an old video card and used that to cool the NB. The board itself did survive that ordeal (briefly) because I remember popping my old 1.6GHz Duron back in it, but it was short lived. In hindsight, I started to feel guilty because that was probably the best mobo I ever had, and was capable of alot more than I thought.