1. Magical cats
Somehow, these cats must be out of the ordinary. Do they have some kind of magical powers? Can they talk? Or are their completely normal cats with magical colors?
2. Superheroes with weird powers
Superhero games aren't hard to find, but how about a superhero with an unusual power? This power can be comedic, creative, or just plain strange.
3. A controversial love triangle
Love is sometimes controversial - but a love triangle? Oh, my!
4. Being a god
Your protagonist is a god. What kind of god? We'll leave that to your creativity.
5. Random chance and/or luck
Is your character randomized? Is the story randomized? Perhaps the game is a practical game, based on playing cards? Somehow, the player shouldn't quite be in control.
6. Defying physics
Reality sucks. Why not give your player the chance to escape it by doing weird stuff that probably shouldn't happen?
7. A terrible protagonist and/or antagonist
Is this hero or villain really bad at his job? Or maybe just a terrible, terrible person?
8. Making peace, not war
Games are always about fighting, killing, and combat. Why don't you put a stop to all the violence and make a politically correct game about finding solutions that aren't quite so bloody?
9. A fangame for something you hate
Show us how you would have told the story of something that grinds your gears - even if it ends in the tragic demise of the heroes you loath.
10. You're not actually the hero (but you think you are)
You only THINK you're doing the right thing. Are you the bad guy the whole time? Or more confused than Don Quixote?