I had one horrible experience with my cable company where they had a robot diagnosing the problem I was having with my connection. From that point on, whenever I was confronted with one of those menus, I'd just mash the '0' button repeatedly until I got a human.
I've found that cursing at the system also works sometimes. Some systems obviously have curse word recognition (or, barring that, a default of "send to human if incomprehensible"). So my conversations end up being:
Machine: Please choose from options x, y, or z.
Me: x.
Machine: Did you say z?
Me: No, x.
Machine: Did you say y?
Me: #*$*&#!
Machine: OK, I'll put you through to a representative.
Saves all the mashing of 0 and having the machine inform me that that's not a valid selection.