I think that it'd be placed in some sort of large announcement that if anyone has any ties to any other kind of community, that they have some sort of advert back to here, and following logical principles people that are actually interested in this place stay for what they like (sprites, fangames, music, O_o and don't forget the community in general) and would contribute properly to what they like.
I think the rupee/rewards system would be very interesting but it seems that it would be sort of temporary, (ie. an influx of people joining and playing for the novelty of the system and it's rewards, then ditching ZFGC.) So it definately should be a quality system, something that isn't just "Oh, let's see how quickly and easily I can get everything." While it wouldn't be that simple I assume people would eventually degrade it to that. Like said before it should be "Hey, he completed his fangame, and alot of people like it!" So a Mod, or Admin generates 10-20 rupees to his account.
Another good idea to the rupee system though is to add functionality to the items you buy. Such as, incorporating another idea before, buying a pass to be permitted into the Spam forum. Even something like the Lens of Truth could just be like some little graphical easter eggs in some posts, like add some code string people can put in there posts or signatures that can be viewed by themselves normally, but others can only see it if they have the lens of truth. I'm guessing you get my ideas for that.
Last, in light of the "ZFGC Website". I think the game of the month contest can be furthered by having it's own page on the website, much like a booth in z3, and things like that can be applied for everything, such as sprite of the week, (but content might be an issue there) and even for music of the week (content might be an issue here also.)
A good thing for this website could be to try to affliate with other game/gamemaking oriented websites also.
Ok, I need to get a shower and go to be now, I'll *hopefully* have more ideas later.
++++++++++++++ ADDITIONAL IDEAS++++++
A ZFGC Commitee.... You know like a group of probably 12 people that are elected by the members here, and it would work much like the congress today, so I'd say about 3 spots go up for election every month, that way, just like in congress there is a steady balance of senority/those with good leadership/experience. I assume this could go bad, but the popularity of the people eventually wouldn't have a factor in this anymore because the people would eventually see that the people aren't adept at their job.
Now, these committee members could have some responsibilities delegated to them from the mods and admins. I'd say the more community oriented things, and this would help decisions because it ultimately would be up to the committee to decide things. (Things like the "Spam Forum Go or Stay Debate") Or even for instating new ideas into the forum... *Gotta go, more ideas later.*