Dynamic Side-Tabs
The "My eBay" area of eBay uses a system of dynamic side-tabs for navigation to child (subordinate) pages. Here are the tabs in the normal state:
Here is the "Saved Stuff" tab in the rollover state:
Once you click on a tab it stays open; closing the previously-active tab:
I think this is an interesting approach to help de-clutter a left navigation bar, which can sometimes contain an overwhelming number of links. The key, however, would be clear groupings of links--with labels that convey a strong "information scent" of the underlying links.















