OK I have some suggestions.
1) First off some spam can be funny, but blatent spamming the hell out of interesting threads or spamming over a question some one has asked is nothing but annoying and disrespectful it should not be tolerated. Like I have said before when people ask for help, sifting through insults and spam to finally have the thread closed because it is off topic is ..... crap for lack of a better word.
2) I think people here don't always post so much because they prefere to use a message provider ( see reasons above ) so maybe fixing the Chat option would give members more reason to log on to Zel and also allow people to thrash things out in the Chat room as oppose to spamming the forums.
3) One reason I myself always check in on Zel is because help is never far away
ex: The MSBlast virus every one with information added some thing to help other members. A forum with upto date info on new virus and how to fix them and security issues or alike, I also think this could bring new members.
4) Another forum that members might find interesting could be life dicussions , girlfriend/boyfriend issues parent issues work issues, School issues, I am the star wars kid issues. I don't know but just a more personal forum.
5) The idea started in the flame forum with the flame contest is the kind of thing that will give older members some thing new, also every one was interested in the riddles titus did, although it was an old thread. But some games, puzzles or contests seem to always be fun and popular.
There are alot of funny people and cool people on Zel, it makes me smile just to think of K_A's Pancake Bunny or Panda pic