What Color is the Dress?!?
This is intriguing me so I am going to join in.
A few factors that come into play with this phenomena:
1. White Balance - click here and read how white balance can change how an image looks in different situations. Wired.com also did a great article explaining this with the dress. Here's a video of another photographer actually demonstrating this on "the dress".
2. Screen Color Calibration - as a photographer if this hasn't been done on my screen then my images are not the correct color. This may be the case with loads of devices. Google it if you don't know how to do this on your own computer.
3. Different parts of the dress have different colors in different light - these guys explain it better.
4. Our eyes do weird stuff - again I have no clue but these guys do.