Just like my post with some web app ideas, feel free to steal any of these.
A fake lottery game
This has already been done several times. You would start with some money (fake money) then buy some tickets and scratch them off. Some would win (more money) and most would lose. Maybe I would hide silly messages in the tickets. The gimmick would be the activity of scratching off the tickets, or maybe spending money on other side treats. Like cigarettes. While smoking, maybe the screen would be hazy. Or maybe you could buy crystal meth, too, and you could scratch tickets really really fast.
And so forth. On to idea number two!
Pick a scab
If you want high-brow, go somewhere else. So, the idea here is obvious, right? The screen shows an ugly scab. You can pick at it. Then it bleeds. Then maybe it heals, and the cycle starts again. Probably been done before.
Pop the pimple
Yeah, so apparently this has already been done too, damnit. But what if the pimples could be superimposed on top of the photos in your album?