That's a very good question, not because it's hard to answer, it isn't it's just my kind of question XD

The objective in a single sentence is to create the "Battlefield 2: Nothing Held Back" modification. To explain what that is though, and what it involves, takes more than the one sentence.
The mod is defined by it's name, "Nothing Held Back", we want to create a mod that makes Battlefield 2 into an all out war situation where none of the involved nations are holding anything back, where they are deploying everything they have to the front-lines of battle. In the long run this will mean modifications such as seeing the most high-tech equipment and weapons in modern military inventories in the game, available to the player, things such as the full on G36K rifle with it's special integrated scope and AG36 (I think that's it's name) grenade launcher, the American F/A-22 Raptor and the Russian PAK FA which will make it's maiden flight next year (obviously that will have to wait till then), maybe the C-130 Hercules transport plane, Destroyers, Cruisers and other naval boats etc. you can imagine the rest yourself.
The mod also aims to achieve a higher level of realism, but not in the same way as the Project Reality mod does. We're not looking for realistic gameplay, and we don't want over realistic vehicles and weapons to distort the balancing in the game and change the gameplay in that respect, we just want a realistic selection of gear available and maybe some realistic gaming environments. Possibly in the future for example, we could add a map in London or New York city centre, made using maps and google earth, which could then be given gameplay balance by adding things like wrecked buses and sand bag defences. Ideas and things like that.
So in summary, the mod team is trying to create a mod which will give people a fun gaming environment where they can mindlessly kill each other with the full might of today's modern armies.