I like the idea of a newcomer of the month or just competitions for newcomers in general so they've got some reason to stick around and continue to post.
Also, speaking of the events idea with forum accounts and usernames being taken. Maybe, if possible, we could have an empty out of accounts that haven't been on in x amount of years and clear up some usernames? I can't imagine that it'll boost activity but it'll free up some usernames for anyone who might come along and join us in the future.