I remade the card game from Final Fantasy 8 using Ruby and Gosu. I mostly did it to get better at pure Ruby, but Gosu was pretty swell. The code stayed pretty clean up until I hit my final session and wrapped the game rules up and added a bot to play against. There are a few concepts I'd still like to learn more about, like ways to do game states, and ways to add time delays without holding the entire game up, like when the bot chooses a cell. There's also no animation or actual game framework, though the card game's rules are in and working.
I think I'm a little sloppy passing so many object pointers around, and I'm sure a few things in here should be modules, but I'm learning as I go. This is miles better than my last "project", which was a horribly sloppy (but perfectly functional) Conway's game of Life.
https://github.com/mikezila/Triple-Triad--RedIt includes art and sound that's copyright square enix, but it's already widely available on the net, and I'm like the 30th person to remake the game using the official art and sound, so I'm not sweating.