I've entered eight codes so far, none winners. Did this by forcing my family along with myself to each eat one of those boxes and entering two codes per day, one on my phone and the other on my wife's phone.
I have now filled out 40 postcards to mail in (I have plenty of extra stamps laying around), twenty for my wife and twenty for me. I will probably suffer the Taco Hell a couple more times before the contest ends, so I believe I will have around 60 entries before it ends.
I'm not expecting to win in any way whatsoever, but man....it would be really nice after sacrificing my colon's structural integrity to the dreaded Quesarito or whatever the hell that thing is called!