This is it:
I do have a Forum which offers free membership to the first 1000 members who register at my Forum. Once my Forum reaches 1000 members, new users will have to pay to register.
My Forum is private, meaning the only thing you see at the Homepage is an image - you do not see any Forum-statistics or any Member-list or anything like that.
So the idea is to show a "Number of Members"-counter.
As I am offering "free membership" to the first 1000 users who register, the counter should countdown from 1000 and use the number of "already registered members" to count the difference.
The Slogan would be something like this:
"Join us today - it's Free for the first 1000 members!"
And the Countdown-timer shows that there are still 236 free memberships available.
How about that ?