I proposed by hacking Chrono Trigger

YouTube video description by TheRealPfhreak:

On October 17th, 2008, I proposed to my (now) Fiancee. Originally I wanted to return to the site of our first date, Mount Baker, near Bellingham Washington. Sadly, there was no discreet way to get her out there. So I turned to the next best thing, digitally recreating the mountain!

But why stop there? I figured I'd try and recreate many of our other favorite memories -- stargazing, dancing, even her favorite song lyrics (from the Princess Bride). I'm a college student who is studying Computer Science, and I wanted to do something unique that used my talents, so I did some research on Rom hacking, as she was playing through Chrono Trigger. (A perennial favorite of mine, I can't wait to buy it for my DS.) I even put in her cat, Cleo!

I had several goals in mind:
First) Keep the area in the context of the original game, the proposal should be a surprise.
Second) Get it done quick! I had the ring, I had the Father's blessing, and you can't sit on either of those for too long. You'll notice some of the NPC collision information is missing (the cat runs through a lot of weird places) and I didn't have time to properly debug every tile.
Third) Place memories that might be poignant enough to remind her of our relationship, while not inadvertently giving away that this was somehow hacked.(See goal #1.)

Overall, it was a resounding success. She had no idea that this wasn't part of the original. She asked, "Hey, are those the Princess Bride lyrics? Do the Japanese really love that movie?" to which I responded, "Yeah! That's probably it! Either that or a bored translator slipping in an easter egg."

When her name appeared on screen (blurred in this video), she glanced over to me (on one knee, with the ring out), wondering, "How did they get my name in this game?" When she saw the ring, she reread the proposal, nodded yes, and said, "You are such a huge nerd! I love this!"

I spent a long time debating whether or not this proposal was awesome or incredibly stupid. Her friends, and my friends helped talk me into it, and it was a huge success!

I built the area by fusing a pre-existing area (Denodoro Mountains) with concepts I had in my mind. Each NPC in the area (save the cat, and the young girl at the beginning) is supposed to be either myself or my fiance.

By TheRealPfhreak. From YouTube. [Story via 1up]