Also, at least in explorer, in the tree view, pressing left repeatly closes the folder you're in (if it's expanded) or moves to the next parent (if it's closed).
Alt-Numblock-* will open the next level of all sub folders under the selected one.
Whooa, this one is nice! Appears to be standard treeview controls too, works in an app I work on as well, except it appears to do fully recursive expansion. Not recommended on unlimited dynamic nodes..