--Introductions to pairings
--Introductions to characters
--Introductions to specific teams (Avengers, Teen Titans, Young Justice, etc.)
--Meta issues about writing
I'm also adding two new possibilities--the first is reviews. Feel free to volunteer to review:
1. Superhero movies/tv shows, old or recent.
2. Trade paperbacks. Since a lot of us fill in canon with TPBs, it would be really good to have some reviews of the key ones. This could be in-depth reviews of one TPB, or perhaps a list of "Essential TPBs to own to understand X character."
3. Current titles. Anything currently ongoing. Want to encourage people to read the new Blue Beetle or Runaways? This would be your chance.
The second is discussions of specific writers or artists. I know I often feel like there are big gaps in my knowledge of the personalities behind the creation of comic books, so I'd love to see more about that. You could either limit it to universe (Frank Miller's work at Marvel) or cover whole careers (Alex Ross in general).
Comment on this thread to claim something! And I'm haunted by the creepy feeling that I've failed to respond to previous volunteers at some point, so if your suggestion slipped through the cracks, please assume I'm negligent rather than ignoring you and try again. *grin*