Another forum I'm on has a photograph competition thread. Basically a subject matter is named. All interested parties have a time frame of around 5 days to get a picture in. After five days no more entries are accepted and 2 or 3 days are used for everyone to vote for their favorite picture.

The winner is announced. Then that person gloats, and chooses another subject matter.

The rules on photo manipulation are pretty open. It's fair game to uses whatever programs you like to alter the image how you like. The only hard and fast rules are that it is a picture you took yourself, worked with by yourself, and it was taken THAT WEEK specifically for the contest.

I'm seeing if anyone is interested in something like that in this forum. I'm not a big photographer, but I enjoy seeing the pictures and voting.