>>The reason it gets hot is because the physical material of the traces and the silicate substrate are resisting electron flow. It's literally frying the chip.
Partly true. In order to overclock it is usually necessary to raise cpu supply voltages above specs, which will directly raise power disapation. What is not commonly known is that the main cause of the added heat is simply the increased clock rate. Digital circuits heat during the transistion period between 1 and 0. (Digital circuits disapate little at logic high or logic low. It's in between that heating occurs.) Raising the clock increases the number switches per second and thus total device disapation. A minor technical point I always thought interesting.