I guess one would assume that shaking a system isn't a good idea, but when like, for example, I'm trying to stick the 2 player controller into the super nintendo while my buddy was playing, i shook the system in the process.  It froze.  My genesis used to do this all the time as well.  Why?  There are no moving parts in the console... If it had a spinning disc in a disc drive, it would make more sense to me, but there is none.  I don't see what causes the system to freeze.  Can someone help me out with this random question?  Thanks.

I don't pretend to know the physics of the system but from my own experience with the SNES and NES, after they get so old touching them will set them off in the manner you are describing. I have complex maneuvers on getting games to run on both of those systems. Never had a problem with the Genesis though. With the SNES I had to put every ounce of force into shoving the cartridge into the SNES to the point that I honestly was surprised it didn't break, then slowly relieving pressure until I let it go completely. Some games were worse than others, and not all of them needed it to be done.

You know maybe it has something to do with how loosely the SNES and NES holds the cartridge. I noticed that I never had that problem with the Genesis and N64 and they both held it pretty tightly. Would explain why if you touch them they go off.

Anyways just to make sure I don't get a stupid comment telling me how off base I am, I said it earlier just like I am saying it now. These are guesses and hypotheticals based solely on my own experiences with how I got the systems to work.

When you shake the system, you shake the cartridge in the slot. This causes the connections to the pins to be broken, which causes the game to freeze. The system must always have a solid connection to the game ROM, since it can read from it very quickly at any time. Like RAM I/O, ROM I/O is immediate, unlike CD drives or hard drives.

Basically, imagine if you opened up your PC and shook the RAM sticks.  The same thing would happen; your computer would immediately crash.