I've created some concepts for the flags for the open source game Nexuiz. It's for the game mode 'Capture the Flag' of course. Whether these get chosen or not I do not know (probably not), other people have submitted their concepts and there is a quite good one.
The blue flag is a base concept by a guy with the nickname 'tZork' on the Alientrap forums (Alientrap is the team working with Nexuiz, and tZork is one of the devs). I just added some detail and other touches to it.
This is a work in progress (not so much to submit the concept, but more because I want to make a real model out of this).
So here are my concepts: