One thing I've been playing with for the last couple of days is dynamic sidebars. I wasn't planning to add such a fancy gimmick, but one thing led to another and I ended up using the Plugin Management code to make a Sidebar plugin. Basically, it enables plugin developers to make sidebar widgets which users can add to their sidebars and reorder. It allows for multiple sidebars and multiple instances of widgets.
The names "Sidebar 1" and "Sidebar