My favorite job interview question was this one. The conference room had a projector on the whiteboard with this:

    char *c[]= {"ENTER", "NEW", "POINT", "FIRST", };
    char **cp[]= {c + 3, c + 2, c + 1, c};
    char ***cpp= cp;
    main()
    {
        printf("%s", **++cpp);
        printf("%s ", *--*++cpp + 3);
        printf("%s", *cpp[-2] + 3);
        printf("%s\n", cpp[-1][-1] + 1);
    }

I just happened to be recently studying all the operator precedence rules and other subtleties in that code, so I got it all right. (Probably wouldn't do as well today :-)

But mainly it was there as a point of discussion to see how you approached such code.

And like most conference room whiteboards, most of the pens were dried out. I tossed those into the trashcan.