Europeans ruined my dinner....or "Why I hate the Metric system"

I am usually a pretty good cook, I've made several course dinners for family and friends that have turned out better than many restaurant meals. Tonight's dinner, unfortunately, was not one of those instances.

The menu:
London Broil
Oven Roasted Brussel Sprouts
French Bread

Let me start by saying, I have cooked London broil several times...however, mostly on the grill. Today was cold and a little snowy, not grilling weather. I decided to try it in the oven. I found a highly rated recipe by Rachel Ray on the food networks website, my usual "go to" recipe site. Season and broil 6 minutes on each side for medium rare. No problem, right? Here's how the events played out:

First side went fine, browned nicely, good crust. Flip. 6 minutes....check temperature 48 degrees...what?! "Maybe the middle of the steak was still refrigerator cold?" Leave it in longer, while I like my meat rare, i don't like it raw and Jake has a food "doneness" paranoia that he's just beginning to outgrow. 5 more minutes, "56 degrees, are you kidding!?" Is there something wrong with the oven?
Leave it a little longer, 10 more minutes elapse...67 degrees. What the hell!...Rachel Ray is a liar, 6 minutes per side, right! I cut the middle open, hard to tell, still some pink but better be sure. Brussel Sprouts go in on the top rack and the london broil gets tented with foil (becuase the outside is DONE) and moved to the bottom.
10 minutes later, brussel sprouts are done, that meat has GOT to be done by now! Check temp. 72 degrees, the thermometer must be broken because it's been in for like an hour now! Take it out...let it rest.
Jake: "Did you check the temp. of this lately"
Me: "Yeah, but something must be wrong with the thermometer, b/c it still was only registering in the 70's and this meat is done"
J: "Do you realize that the thermometer is reading in Celsius?"
Me: "F@$%#!!!!!!!!!"

There is a little button in the back of our digital thermometer that switches the readings from F to C. I must have inadvertatly hit the button and since I was checking the temp. with the meat still in the oven (rack pulled out) I didn't see the little C on the digital readout. Sorry Rachel, I shouldn't have blamed you, you know what you're talking about, I just can't read.

The meat was overdone....way overdone! Jake was sweet, saying "it's ok, just put some A1 on it". We had no A1. Instead, we used some hot sauce we had in the fridge. With the hot sauce, it was still overdone. Inedible to me, Jake sweetly choked it down. The dog loved it.

What a fiasco...oh well, at least the bread was good.