[kh99]

Maybe something like

SELECT userid, username, posts FROM vb_user ORDER BY posts DESC LIMIT 10

where 'vb_' is whatever your TABLE_PREFIX is, of course.

For some reason when I used this in the Maintenance Execute SQL Query box in the ACP, the LIMIT didn't work, so I don't know, maybe there's something wrong with that syntax.

Of course the above would have to be executed at the correct times. There's probably a way to do a query on the posts table to find out how many posts were made by each user for any time period.