This would be nice. If there's too much content in a post, you can simply make the user click on the "+" to see it in a box.
picture is worth a 1000 words:
http://www.flooble.com/scripts/expand.php
Any takers?
this would be nice for those like like to post several images in their posts.
There are already several Spoiler mods around, that would just be a more dollied-up version of one. I'm sure you could take code from an existing mod and use css to style it. Just be sure to credit the author of the mod you're using as a base.