"Anybody who owned a modem in the 90s knows how dangerously addictive these games are."

As embarrassing as this is to admit, I was actually addicted to Idle RPG at one point. This is the IRC game where you level up based on how long you can go without saying anything.

Or a TI83 during high school.

There's still plenty of room in the market for similar games -- pick your theme: sci-fi, fantasy, pirates, ninjas, vampires, etc.