As mentioned on this week's MacBreak Weekly: Plastic Bullet!
Harkening back to the great icons of the cheap camera crowd: the Diana, the Holga, the Lomo, Plastic Bullet gives you a series of options of your shot with random focus issues, color shifts, light leaks, lens flares and not a little bit of serendipity.
There's a weird sort of disconnect when you employ the latest high-tech gadgetry to replicate the world's most famous low-tech cameras.
And then you look at your results and you find your "accidental masterpiece."
Plastic Bullet for the iPhone: two bucks on iTunes.