Administer > menus > primary links > add menu item.
It's not that hard. I even cleaned it up some while ago (certain menu items stood double if not triple in the menu settings).
P.S. That bar isn't like a block (too bad it isn't), so I guess kz1 hacked around the block-settings. This means you can't turn it off or on, neither change it's place. The very same for the private messaging item.
To Razgriz,
The search tools work perfect for me; I'm not seeing where you complaign about.
Edit:
Made something like that in the primary links block. Still needs to be a little more fancy (icons, descriptions, etc). Have fun with it.
P.S.
It's very nice, such games-link. But there are soo many nodes with a messed up tagging (stating they are compatible with Cube Engine while they are clearly not). Some people are tagging their content brainlessly. I think some gui is required here.
I already cleaned up several nodes which used to wear the Cube category tag, while they aren't compatible with it at all. Perhap some other admins could help to clean up the others also. Remember, it's the tags are meant to show off which game the node is compatible with, not if it is potentional compatible (so if content is packaged for the Sauerbraten directory, it isn't compatible with Red Eclipse unless the node provides a version packaged with that directory also).
I seriously miss a dropdown menu for this...