MW2: I got glitched out of the map one in sub base and i could walk on water cant remember how to do it
Black Ops: On Ascension i went down and a zombie pushed me into a pole and i couldn't die (i think its patched now)
MW3: On Resistance where you go to the main building with 2 entrances go into the square, jump into the car spaces, blow up the blue car and jump on it, go prone and move until your inside the bonnit
The Mw3 glitch is the only one that works, theres a video on my youtube