Stuck on You
Streambed near Swiftcurrent Lake (Fluid Refraction). 

A woodland stream under dappled sunlight stopped me in my tracks, and inspired me to sit for a while and contemplate the quicksilver patterns of reflected and refracted light dancing over the colorful stones of the alluvial stream-bed. I was fascinated at how many things were at work in that little patch of sunlight -- optics, geology, hydrodynamics, thermodynamics.  I couldn't help but be humbled at the complexity of our universe being displayed with such elegant beauty.
Streambed of the Middle Fork of the Flathead River

Flathead River Streambed

I found the middle-fork of the Flathead River to lie in a broad bed with a deep (looking) central channel flanked by wide but shallow pebble fields on either side.  What a collection of colors!  The river-worn pebbles were a dozen different shades and formed a natural tile mosaic.
One Thousand Roses
Cube, Pyramid, Tetrahedron
Refraction
Green Flash.
I've heard about this optical phenomenon, seen only at sunrise or sunset under certain conditions, but I'd never seen it, much less photographed it, until last December.  If you're curious about the phenomenon, you can start by looking at Wikipedia's articel, http://en.wikipedia.org/wiki/Green_flash.  To answer Paul's question, the flash was just that, very brief.  One or two seconds.

DP072-2013  Posted March 13; processed ditto
The uncropped full size green flash shot can be seen here, http://smu.gs/Yrp6U9, along with the other two shots in the same 'Arizona Skies' gallery.

This composite features images taken a few seconds before, at, and a few seconds after the flash.  The camera times are respectively 5:25:04 pm, 5:25:17 pm, and 5:25:30 pm

Note the overall greenish cast to the entire shot at 5:25:17 pm compared with the bracketing shots.  Note also the tiny turquoise green spot just at the horizon where the sun disappeared (clearly visible in the larger sizes)

Tucson, AZ
December 28, 2012

For the three shot sequence, before, at,  and after the green flash, I did minimal processing either in Lightroom or Photoshop beyond some minor exposure adjustment to try to get the overall exposure in each shot similar, based on eye-balling the histogram.  I applied the same noise reduction to each, and that was about it.  I was shooting in aperture priority,  RAW, AWB, with the camera set to make minimal internal adjustments .  Any color differences you see were present in the sky.
A study in the color that can be hidden in nearly monochrome images, especially in "white" light such as that from the sun.  Simply amping up the saturation in photoshop brings the colors vividly to life.  In contrast, doing a BW conversion, and seeing little detectable change re-enforces just how 'hidden' the colors were.
The starting image (referered to as the original below) is a closeup of the perforations of a "sun-brella" that is blocking the sun, which is itself being screened by low thin clouds.

DP071-2013.  Posted March 12; processed March 11; taken March 10.

The four frames, clockwise, starting in the upper right, are:
(1)  Original full color;  (2)  100% saturation applied to (1);   (3) BW conversion of (1), rotated 180 degrees;  (4) Two filter layers, Fresco and Plastic Wrap, applied at reduced opacity to (2), followed by a 180 degree rotation.

The full sized images of these four frames, all in the same orientation, can be see in my 'Fun with Filters' gallery here.  In those images you can get a better sense of details of the colors brought out in (2), and the effect of the filters, which is somewhat difficult to see in this composite.  http://arctangent.smugmug.com/Photography/Creative-Alterations/Fun-with-filters/10668106_75xhP9  (They're image set #38, currently at the end of the gallery)
Stuck on You
Stuck on You
Stuck on You
See photo in original gallery.