There's a block included with the forum, but that displays only as a side block (in the left or right column).
I assume you're referring to the center block, i.e. the block that displays in the center column. That actually uses the new center block API that will only be introduced with Geeklog 1.3.8. I think Blaine has a tutorial on his site explaining how to add this to 1.3.7.
bye, Dirk