This is a question posed by someone on Reddit and it generated thousands of responses, but one response in particular most definitely won the day.
The headline to this reply was: "A wife, three beautiful children and frankly my life as I know it..." He followed up this promising start with some more details:
Back in Jr. High, I liked a girl and flirted with her quite a bit. One time, during a band trip, we stopped at a gas station and she bought me a pack of gum. I tried to pay her back $1 but she refused. So, I slipped the $1 in her pocket. She then slipped the dollar in my backpack and so began the back and forth with the $1 bill. We found silly ways to give it back and forth. I mailed it to her house. She stuffed it in a gum wrapper and offered me a piece. I then decided that I would ask her out on this $1. I wrote, "Will you go out with me" on it and put it in a note and gave it to her. She said yes (of course, it would be a terrible story otherwise, I suppose).
About four years later, I still had the same dollar kept away. On our anniversary, I wrote "Will you marry me" on the bottom of the dollar. We have been married for 15 years and have three awesome kids. We still have that dollar stored away.