Current theme: none this week
During the Christmas of 2011, PhotoSE introduced themes for the Picture of the Week (PotW) contest. Themes were an idea that had been floating around for some time, almost since the inception of the PotW itself. The idea of a Christmas theme was brought up a few times in early December, and a spur of the moment decision was made to do themes for the rest of December. Seeing as themes were sprung on the membership rather suddenly, here is the official statement about PotW Themes.
Picture of the Week Themes
Every so often, a picture of the week theme will be announced. Themes will impose additional rules above and beyond the normal picture of the week contest, usually revolving around acceptable subject matter, and any other photographic requirements, for submissions to qualify. All theme specific rules will be included in that weeks PotW details, above the standard set of rules. Any non-qualifying submissions will be deleted. If your submission is deleted for lack of qualification, you will still be allowed to submit one item for that week if it complies with the requirements of the theme.
As far as scheduling goes, we will always announce themes before hand. We will give members at least two weeks advanced notice. Details of an upcoming theme will be linked in the PhotoSE header below the current weeks winner details and next to the current weeks winning photo. We will try not to have themes more frequently than once a month, however during special times of the year, say Christmas or other holidays, we may have an extended period of themes (i.e. two strait weeks of Christmas/Holiday theme).
There are a bunch of ideas for PotW themes. Christmas seemed like an easy way to start, as there is usually a ton of great themed subject matter laying around that can be photographed. Holidays aside, if you have an idea for a theme, PLEASE feel free to tell us. You can use the PotW Theme Ideas thread to post ideas for themes. Please keep each theme in its own separate answer. If a theme is picked up for a month, the answer there will be deleted, and its contents copied into a "Picture of the Week Themes Archive" thread for historical purposes (and that thread will be locked so as not to allow any form of tampering.) Removing past theme ideas from the thread will allow new ones to be voted on more appropriately, allowing the best of new theme ideas to float to the top via votes. If we do not have any theme ideas for a given month, the moderators will do what they can to either garner ideas from the membership (most likely through the PhotoSE chat room), or come up with an idea of their own.
Comments, Considerations, Disputes
The idea for Themes is a community-born idea, and just like the rest of StackExchange, should be community managed. If you have any comments to make about themes for the picture of the week, feel free to voice them here, or in the PhotoSE chat room. I am usually there myself, although not always available to chat. I will try my best to respond to comments so long as they are brought to my attention (i.e. use @jrista to highlight a chat message for my attention). Our active core membership may also respond as well, so other members you might bring your comments to attention on are @rfusca and @mattdm, amongst others (pretty much any of the top-rep users on the site will probably be able to offer some assistance, even if that is simply to bring it to one of the moderators attention.) We hope that themes are already pretty open and accessible as ideas for themes are completely open to the community membership to offer and vote on, however were open to officially refining the idea and process if it is necessary.