It's been on Wikipedia for years: http://en.wikipedia.org/wiki/List_of_lists_which_do_not_include_themselves http://en.wikipedia.org/wiki/List_of_lists_which_d

It's been on Wikipedia for years: http://en.wikipedia.org/wiki/List_of_lists_which_do_not_include_themselves http://en.wikipedia.org/wiki/List_of_lists_which_do_not_incl... And it actually does something useful.