INTERCAL has made many contributions to the state-of-the-art for numerous modern languages. My personal favorite sides with the author with the implementation of COME FROM, which is indisputably a vast improvement over the much maligned GOTO. It's so handy that it's been ported to Python! [0]
That was hilarious. Especially the precedence section. The brilliance behind INTERCAL's design also inspired work in the functional programming domain:
Modules, not classes. Also, while Python has True and False, 0 is falsy and all other numbers are truthy. There are a lot of problems with Perl, but picking on these two is a bit silly. They belong to the class of superficial issues that all languages suffer from.
Perl lends itself to craziness because of the notorious TMTOWTDI principle taken to the extreme - Intercal can indeed appear more sane than many Perl programs I have had the misfortune to use and (shudder) update.
[0] http://entrian.com/goto/