Pong game . Nah, the good people of TDC would kill you if you did .
Or an offline multiplayer deathmatch game. Those are easy. I started off with one of those even though I couldn't draw, and plenty of people loved it. And they're very improvable. Just look at FactorX, Trigger Happy 2.
Or since you can do graphics, get Adrift and make an adventure game.
Disclaimer: Any sarcasm in my posts will not be mentioned as that would ruin the purpose. It is assumed that the reader is intelligent enough to tell the difference between what is sarcasm and what is not.