A very nice hack for MicrosoftWindows that replaces its Explorer interface with a user interface more or less like NextStep alike.

LiteStep has suffered many (too many?) times from important shifts in their focus, as they have forked/merged/changed developers over and over, but all in all, it is quite a successful free software project for MicrosoftWindows systems.

Its web site?

http://www.litestep.net/

http://www.litestep.com/