Let's go with something simple, but still specific enough to spur a little bit of our creativity: landscape. I'd say it could be any kind: mountains and fields, forests and jungles, cityscapes, streetscapes, seascapes, snowscapes, natural or built.
The rules are: Photos must be taken during this montH Photos must be taken by the posting member Photos must be taken with a camera phone Users post only one photo per entry Users can change the entry only once Users must name the phone they used (so I could include it for voting) Last three days of this month are for voting