This is an absolutely true story.
After dinner one night, my wife and I decided to go for a walk in the park. We headed off down a walking trail when I saw a DVD lying on a rock. The DVD was in a case and the words "Grand Titas vol. 3-13" was written on the disc. I had no clue what that meant, but suspecting pornography, I decided to take the DVD. I figured if it wasn't porn, then I was doing my part in cleaning up the park and for that, I felt good about myself.
I took the DVD home, put it in my PS2 and it began to play. Immediately, Rick Astley's "Never gonna give you up" blasted from my TV. The entire video was a montage of Rick Astley pictures and I was informed that I had been Rick Rolled. I sat back and was amazed that someone spent the time to make the DVD and hide it on the walking trail.
One day, I plan on leaving it somewhere in public so someone else can pay it forward.