In the campaign Dead Center, on the third level, Mall, there is a spot where tanks and other zombies can't get you. In the beginning, go up the escalator and then to the doorway with the fence blocking it halfway (hint: this is the right way to go).

Once you get there there are some shelves shove over to the left. There is some bodies in front of them. Go to the two shelves, not the one that says "information". In between those two there is a little corner. Try to get in there. Ways that work are crouching then jumping, just running in fast or getting lucky. But this is not only for the tank! It also works for chargers!

I have not tested on witches or boomers (although I imagine they would just barf on you anyways). The worst possible is spitters because there is only one way out. Hunters cannot pounce on you but they will crawl in and start hitting you which is worse.

The horde can get in. Smokers can toungue you but they have to be in front of the opening. Tanks just climb on top and in the opening and spaz out.

Oh! and I haven't tested it out on jockeys.