The dirty dirty Oven

Really, that's as clever a title as I could come up with, sorry all.

Here's the deal.  We have this oven, ya know.  The oven that hasn't been super cleaned since we moved in, O eons 2.5 years ago.  Anyway, it's dirty and I don't dirty like there's a few pieces of burnt whoknowswhat stuck to the bottom of the oven, I mean dirty like everytime we cook anything, a cloud of smoke comes out when we open the door.  It smells a bit like burnt to a crisp toast.

I've tried to just scrub it, but you all know that really only works if it's just mildly dirty.  This thing is severely grotesque.

Last night, I cooked my "famous"  pizza.  It was delicious, but the smell that came from that stewing-in-its-own-filth oven of mine was, to say the least, unappetizing.  

So, what's a girl to do?  How do you get that crusty-disgusting oven clean?  Suggestions? Please, we're dying from a black cloud of smoke that releases from the oven everytime we open it! Yuck!

Credit:

This oven is not my oven, but it may as well be.