Try NeXSTEP V3.3 (VMWare)

[nikonian]

Always the experimenter, and as a Mac user and lover, I was simply *delighted* when I discovered a VMWare image of "NeXSTEP" 3.3:

http://osvirtual.net/en/nextstep-3-3-with-drivers-vmware/

Well worth a whizz - quite fun, and I find it very interesting to see what Mac OS X is based on :)

Here's a video I made in VMWare, of me booting it:

http://www.youtube.com/watch?v=WmSnomHQBng




For the un-initiated:

http://en.wikipedia.org/wiki/NeXTSTEP

[MadmanRB]

Yeah I know of nextstep.
There is GNUstep, I did try it once and liked it okay but I would never use it on a regular basis.

[Jakin]

Fun to use. But sorely lacking for everyday use. If its the UI that you really like, WindowMaker can be installed in linux :)