Here's one from a short walk along some train tracks a few miles away from my place. There was some interesting graffiti all over the place, and of course loads of empty spray paint cans.
This is my final image after it being "done" at least 5 times haha. Processed with Lr 3, Silver Efex Pro 2, and PS CS5. Once in CS5 I used the history brush for almost all the contrast adjustments. (extremely simple yet precise) There is also a luminosity mask that added a nice bit of contrast. After I had the contrast mostly to my liking I used the High Pass sharpening filter on a layer copy set to overlay with a mask for some selective sharpening.
Tamron 17-50 @ 17.01mm
f/11
ISO 80
1.3 seconds