Programming

Not QUITE a program, but I'd have to say my own little GBA ROM hacks for the original Fire Emblem. On account of the following story...

IIRC, it was 2007, and I was a senior in high school, reorganizing some of the stuff for the robotics team, in the cabinets in the big science classroom where we met. There were some freshmen interested in the team (season wouldn't start for a while yet) who'd taken to hanging out there, after school.

They all had laptops and I recognized the menu theme when one of them pulled up Fire Emblem in an emulator, from across the room, and immediately called out "Who's playing Fire Emblem?". When I went over and saw he was using Virtual Boy Advance, it occurred to me what I had in my pocket. Or rather what happened to be ON the flash drive in my pocket.

At the time, I didn't have my own laptop, so my flash drive had years worth of random crap on it. And over the years, I spent a LOT of time tinkering with ROMs and VBA over the years. In addition to a few copies of different hacked ROMs and save files, I had a portable hex editor, and a LOT of text files with hex tables and memory maps and other research I'd collected over the years.

So, yeah, I pulled out the flash drive, said "Wanna see something cool?" and proceeded to apply many crazy hacks as I could think of, in the most obtuse manner possible, just editing hex values directly in memory as the game was running. Free XP, free items, end game equipment, sprite swaps, etc. At one point, one of them says something like "What kind of wizard ARE you?!"

It's what comes to mind for me when you say "cool" because I like to think I inspired those kids to get into software and programming themselves, or at least consider it as an option. They certainly stuck around with the team for the rest of the year. Also, it inspired ME to really realize how much I'd grown just by tinkering and being curious, and how much you can accomplish through incremental effort.