It was a 5-seconds dream, but I still remember it.
On the home page, where there is the last topic of the category, right and left arrow where added to enable the user to surf among the lastest topics of a category from the home.
I can't say I see the benefit of having such a feature. It would require a bigger query and more code than should be there for a forum home. If you could do that then what would be the point of even clicking on the forum to view the thread list.