Competitive coding
Fully on-chain games have many interesting properties that I've written about in the past. One that has always stood out to me as a developer is the fact that botting the game is a feature. It would be considered cheating in most games because it gives an unfair advantage against normal players.
But what if using bots was the only way to play? What if writing code was the game?
In college, I had a professor who assigned each student to write a program that would play the game of Clue. If you're not familiar with the game, the premise is that there was a secret murder in a mansion. The point is to ask questions of your fellow players to find out what they know and guess the secret of the crime before anyone else.
The interesting part was seeing the game be simulated and watching your code compete against others. Because of the nature of the game, there wasn't one perfect strategy. If you coded the theoretically most optimal approach, someone else could write a program that assumed you were playing perfectly to deduce what you knew faster.
I think this concept belongs on blockchain. You could implement any game as a smart contract, add a leaderboard, achievements, or whatever else you want to make it more competitive. Then players compete by uploading their own contracts and picking fights with other players. It's robot boxing.
-Luke
P.S. the concept is a game, but it would also work well for running company sponsored hackathons. Monetize through b2b sales where you create a custom game for the sponsor. Offer prizes to the top developers.